BX25 v0.1 - House Rules to Expand B/X D&D to Level 25

BX25, also known as BXXXV (pronounced "Bee-Triple-Ex-Vee" if you're nasty*) is my set of house rules for expanding the 1981 Basic and Expert D&D system (or "B/X") so as to allow characters of up to level 25. The Expert Set had guidelines for expanding the system in such a way, and this is my attempt to do so, with certain alterations in line with my personal taste.

The twist is, I want to do this without using the later Companion Set or the Rules Cyclopedia. The BECMI version of D&D has a lot of fiddly extra details and added complexities that I don't necessarily want to deal with in a B/X game, like "attack ranks" for demi-human classes, weapon mastery, a new skill system, paladins and druids, etc. Don't get me wrong, I really like the Rules Cyclopedia, but as I've said before, it's just a lot to deal with. BX25 is meant for higher-level play without straying too far from what's already in those short B/X books.

If my BX + RC Bridge Rules are like Zenopus' Bridge Tables in that they allow you to supplement one preexisting set of rules with another, then BX25 is more like Meepo's Holmes Companion (found HERE) or the B/X Companion from Running Beagle Games; The point is to add onto one version of the game without needing to reference another whole version. You just need the B/X rules and this short document, no "BECMI" required.

Why level 25, when the BECMI sets and the Rules Cyclopedia go to level 36?

1. I think that stretching character advancement to level 36 is overkill. Look at how thief skills got worsened in the Rules Cyclopedia compared to B/X, for example. When you add more levels to B/X, you can either take the basic metrics of advancement (saving throws, HP, to-hit rolls, class abilities like thief skills and spells-per-day) and thin them out, or you can add new abilities (multiple attacks! new thief skills! new spell levels!), or you can just take all of the numbers and make them bigger/better (which can still require new subsystems when you run against certain limits - "Attack rolls still miss on a 1, so let's add extra damage instead,"). I wanted to avoid the first method, and use the second and third methods sparingly.
2. It takes so many experience points just to earn 25 levels, let alone 36. I tried to make the math work out in such a way as to give players 36 levels worth of capabilities in only 25 levels (at least in some regards), so players would feel truly powerful by level 25. I think you get more "bang for your buck" this way, or rather, "better advancement per level," while mostly still sticking to just B/X. And frankly, players are more likely to see level 25 than 36, so it seems like less wasted effort.
3. The Companion Set that actually did get released for BECMI went up to 25, and I thought it would be cute to follow suit. Besides, this way you get 3 levels of Basic, 11 levels of Expert, and 11 levels of Justin's Overpowered Antics. Dare I say it, it struck me as being somewhat more elegant.

Did I hit my design goals? Do those goals even make sense? Who knows? This is a very rough draft, of course. As with my B/X + RC Reference Sheet that I mentioned above, I'd like to organize all of this into a short PDF with better layout and convenient tables. It wouldn't hurt for me to playtest it, either. Feedback is welcome, as usual.

*I thought about calling it BXJ, for "Basic/Expert/Justin", but then all I could think about was stuff like "One time, this super hot sorceress totally gave me a BXJ out behind the Comeback Inn," and I suddenly felt the need for a different acronym so I could focus on important things like rules minutiae for a tabletop game from 1981. And no, you wouldn't know her. She's from Canada Greyhawk. Anyway, special thanks to Anxiety Wizard for the better title(s).

BX25 (or BXXXV) - Version 0.1

Level Limits

• The Cleric, Fighter, Magic-User, and Thief classes are now limited to a maximum of Level 25.
• The Dwarf, Elf, and Halfling classes are now limited to a maximum of Level 15.

Experience Points Needed Per Level
Cleric

• Level 15: 800,000 XP
• Level 16: 900,000 XP
• Level 17: 1,000,000 XP
• Level 18: 1,100,000 XP
• Level 19: 1,200,000 XP
• Level 20: 1,300,000 XP
• Level 21: 1,400,000 XP
• Level 22: 1,500,000 XP
• Level 23: 1,600,000 XP
• Level 24: 1,700,000 XP
• Level 25: 1,800,000 XP

Fighter

• Level 15: 960,000 XP
• Level 16: 1,080,000 XP
• Level 17: 1,200,000 XP
• Level 18: 1,320,000 XP
• Level 19: 1,440,000 XP
• Level 20: 1,560,000 XP
• Level 21: 1,680,000 XP
• Level 22: 1,800,000 XP
• Level 23: 1,920,000 XP
• Level 24: 2,040,000 XP
• Level 25: 2,160,000 XP

Magic-User

• Level 15: 1,200,000 XP
• Level 16: 1,350,000 XP
• Level 17: 1,500,000 XP
• Level 18: 1,650,000 XP
• Level 19: 1,800,000 XP
• Level 20: 1,950,000 XP
• Level 21: 2,100,000 XP
• Level 22: 2,250,000 XP
• Level 23: 2,400,000 XP
• Level 24: 2,550,000 XP
• Level 25: 2,700,000 XP

Thief

• Level 15: 880,000 XP
• Level 16: 1,000,000 XP
• Level 17: 1,120,000 XP
• Level 18: 1,240,000 XP
• Level 19: 1,360,000 XP
• Level 20: 1,480,000 XP
• Level 21: 1,600,000 XP
• Level 22: 1,720,000 XP
• Level 23: 1,840,000 XP
• Level 24: 1,960,000 XP
• Level 25: 2,080,000 XP

Dwarf

• Level 13: 800,000 XP
• Level 14: 1,000,000 XP
• Level 15: 1,200,000 XP

Elf

• Level 11: 850,000 XP
• Level 12: 1,100,000 XP
• Level 13: 1,350,000 XP
• Level 14: 1,600,000 XP
• Level 15: 1,850,000 XP

Halfling

• Level 9: 300,000 XP
• Level 10: 600,000 XP
• Level 11: 900,000 XP
• Level 12: 1,200,000 XP
• Level 13: 1,500,000 XP
• Level 14: 1,800,000 XP
• Level 15: 2,100,000 XP

Saving Throws
Cleric

• Levels 13-16: Poison 3, Wands 5, Paralysis 7, Breath Attack 8, Spells 7
• Levels 17-20: Poison 2, Wands 3, Paralysis 5, Breath Attack 5, Spells 5
• Levels 21-24: Poison 2, Wands 2, Paralysis 3, Breath Attack 2, Spells 3
• Level 25: Poison 2, Wands 2, Paralysis 2, Breath Attack 2, Spells 2

Fighter

• Levels 13-15: Poison 4, Wands 5, Paralysis 6, Breath Attack 5, Spells 8
• Levels 16-18: Poison 2, Wands 3, Paralysis 4, Breath Attack 3, Spells 6
• Levels 19-21: Poison 2, Wands 2, Paralysis 2, Breath 2, Spells 4
• Levels 22-25: Poison 2, Wands 2, Paralysis 2, Breath 2, Spells 2

Magic-User

• Levels 11-15: Poison 8, Wands 9, Paralysis 8, Breath 11, Spells 8
• Levels 16-20: Poison 5, Wands 6, Paralysis 5, Breath 8, Spells 4
• Levels 21-24: Poison 2, Wands 3, Paralysis 2, Breath 5, Spells 2
• Level 25: Poison 2, Wands 2, Paralysis 2, Breath 2, Spells 2

Thief

• Levels 13-16: Poison 8, Wands 9, Paralysis 7, Breath 10, Spells 8
• Levels 17-20: Poison 6, Wands 7, Paralysis 5, Breath 8, Spells 6
• Levels 21-22: Poison 4, Wands 5, Paralysis 3, Breath 6, Spells 4
• Levels 23-24: Poison 2, Wands 3, Paralysis 2, Breath 4, Spells 2
• Level 25: Poison 2, Wands 2, Paralysis 2, Breath 2, Spells 2

Dwarf and Halfling

• Levels 7-9: Poison 4, Wands 5, Paralysis 6, Breath 7, Spells 8
• Levels 10-12: Poison 2, Wands 3, Paralysis 4, Breath 4, Spells 6
• Levels 13-15: Poison 2, Wands 2, Paralysis 2, Breath 2, Spells 4

Elf

• Levels 10-11: Poison 6, Wands 7, Paralysis 8, Breath 8, Spells 8
• Levels 12-13: Poison 4, Wands 5, Paralysis 7, Breath 6, Spells 6
• Level 14: Poison 2, Wands 3, Paralysis 6, Breath 4, Spells 4
• Level 15: Poison 2, Wands 2, Paralysis 5, Breath 2, Spells 2

Spells Per Day
Cleric (First to Fifth Level)

• Level 15: 6/6/5/5/5
• Level 16: 6/6/6/6/5
• Level 17: 7/6/6/6/6
• Level 18: 7/7/7/6/6
• Level 19: 7/7/7/7/7
• Level 20: 8/8/7/7/7
• Level 21: 8/8/8/8/7
• Level 22: 9/8/8/8/8
• Level 23: 9/9/9/8/8
• Level 24: 9/9/9/9/8
• Level 25: 9/9/9/9/9

Magic-User (First to Sixth Level)

• Level 15: 5/4/4/4/4/4
• Level 16: 5/5/5/5/4/4
• Level 17: 6/5/5/5/5/5
• Level 18: 6/6/6/6/5/5
• Level 19: 7/6/6/6/6/6
• Level 20: 7/7/7/7/6/6
• Level 21: 8/7/7/7/7/7
• Level 22: 8/8/8/8/7/7
• Level 23: 9/8/8/8/8/8
• Level 24: 9/9/9/9/8/8
• Level 25: 9/9/9/9/9/9

Elf (First to Fifth Level)

• Level 11: 4/4/3/3/2
• Level 12: 4/4/4/4/3
• Level 13: 5/4/4/4/4
• Level 14: 5/5/5/4/4
• Level 15: 5/5/5/5/5

Thief Skills

• Level 15: Pick Pockets 135%, Climb Upside-Down 89%, Throw/Mimic Voices 50%, Read Languages 81%, Spell Backfire 10%, Sneak Attack Damage Multiplier 3
• Level 16: Pick Pockets 145%, Climb Upside-Down 90%, Throw/Mimic Voices 55%, Read Languages 82%, Spell Backfire 10%*, Sneak Attack Damage Multiplier 3
• Level 17: Pick Pockets 155%, Climb Upside-Down 91%, Throw/Mimic Voices 60%, Read Languages 83%, Spell Backfire 9%, Sneak Attack Damage Multiplier 3
• Level 18: Pick Pockets 165%, Climb Upside-Down 92%, Throw/Mimic Voices 65%, Read Languages 85%, Spell Backfire 8%, Sneak Attack Damage Multiplier 3
• Level 19: Pick Pockets 175%, Climb Upside-Down 93%, Throw/Mimic Voices 70%, Read Languages 87%, Spell Backfire 7%, Sneak Attack Damage Multiplier 3
• Level 20: Pick Pockets 185%, Climb Upside-Down 94%, Throw/Mimic Voices 75%, Read Languages 89%, Spell Backfire 6%, Sneak Attack Damage Multiplier 3
• Level 21: Pick Pockets 195%, Climb Upside-Down 95%, Throw/Mimic Voices 80%, Read Languages 91%, Spell Backfire 5%, Sneak Attack Damage Multiplier 4
• Level 22: Pick Pockets 196%, Climb Upside-Down 96%, Throw/Mimic Voices 85%, Read Languages 93%, Spell Backfire 4%, Sneak Attack Damage Multiplier 4
• Level 23: Pick Pockets 197%, Climb Upside-Down 97%, Throw/Mimic Voices 90%, Read Languages 95%, Spell Backfire 3%, Sneak Attack Damage Multiplier 4
• Level 24: Pick Pockets 198%, Climb Upside-Down 98%, Throw/Mimic Voices 95%, Read Languages 97%, Spell Backfire 2%, Sneak Attack Damage Multiplier 4
• Level 25: Pick Pockets 199%, Climb Upside-Down 99%, Throw/Mimic Voices 99%, Read Languages 99%, Spell Backfire 1%, Sneak Attack Damage Multiplier 4

Explanation of Thief Skills

• Pick Pockets: The default rules apply.
• Climb Upside-Down: This works just like the "Climb Sheer Surfaces" ability, except that it applies to climbing overhangs, climbing upside-down, crossing ceilings horizontally without falling, etc.
• Throw/Mimic Voices: This is the ability to mimic the voices of other people or the calls of animals or monsters convincingly with one's voice, as well as the ability to "throw" one's voice like a ventriloquist in order to make it sound like it comes from a different source or direction.
• Read Languages: Just as a Thief who reaches Level 4 can "read languages" with an 80% chance of success, a Thief of Level 15 or higher has an even greater chance of success at this ability.
• Spell Backfire: Just as a Thief who reaches Level 10 can cast Magic-User or Elf spells from a  scroll with a 10% chance that the spell will "backfire" and create an unexpected result, a Thief of Level 17 or higher has a lesser chance of such a backfire.
• Sneak Attack Damage Multiplier: The damage done by a Thief's "backstab" or sneak attack is usually doubled. At Level 15 it is instead tripled, and at Level 21 it is quadrupled.

Special Uses of Thief Skills

• Balancing: A Thief can balance on a narrow ledge, and even walk along it, at the same percent chance that they can Climb Sheer Surfaces. A Thief can balance on and walk across a tightrope or high-wire at the same percent chance that they can Climb Upside-Down. Naturally, the ledge/tightrope/etc. must be strong and secure enough to support the weight of the Thief and their equipment.
• Disguises: If a Thief is able to obtain a convincing costume, the necessary props, etc. in order to wear a passable disguise, they can attempt to keep the ruse undetected at the same percent chance that they can Throw/Mimic Voices. This chance is rolled by the DM at the time the disguise is first donned; as with the Move Silently and Hide in Shadows skills, the Thief does not know if the attempt was successful until the reactions of other characters make the result obvious. If a Thief does something noticeably suspicious or "out of character" while disguised, the DM should feel free to re-roll for the skill. A Thief who attempts to disguise oneself as a specific person or an inhuman creature, rather than a generic type of person (just a typical guard/beggar/merchant/what-have-you) should require many more re-rolls than usual, and it is up to the DM's discretion whether or not to even allow the attempt. If the DM denies the attempt outright, they should let the player know.
• *Using Magic Wands: At Level 16, Thieves gain the ability to cast Magic-User or Elf spells from a wand with the same chance of a backfire as with a scroll.

Multiple Attacks Per Round

• Fighters gain a second attack per round at Level 15, a third attack per round at Level 20, and a fourth attack per round at Level 25.
• The Dwarf, Elf, and Halfling classes still attack as a Fighter of the same level, and they likewise gain a second attack per round at Level 15.

Chances to Hit

Apply the following bonuses to characters' attack rolls at the following levels. (An extended version of the Character Attacks Table may be provided in the future, but this should achieve virtually the same effect.) An attack roll of 1 always misses.

• Fighters Level 16-18 and Clerics/Thieves Level 21-24: +2 to hit.
• Fighters Level 19-21 and Clerics/Thieves Level 25: +4 to hit.
• Fighters Level 22-24: +6 to hit.
• Fighters Level 25: +8 to hit.

Hit Points Per Level

• At Level 15 and above, Fighters and Thieves gain +4 HP per level.
• Optional Rule: At Level 10 and above, Fighters and Thieves gain +4 HP per level.
• At Level 15 and above, Clerics and Magic-Users gain +2 HP per level.
• Optional Rule: At Level 10 and above, Clerics and Magic-Users gain +2 HP per level.
• At Level 10 and above, Dwarves gain +3 HP per level.
• At Level 10 and above, Elves gain +2 HP per level.
• At Level 9, Halflings gain +1d6 HP. At Level 10 and above, Halflings gain +2 HP per level.