If I give max-level player characters a 1-level multiclass dip, will it cause any major problems?

Question

My players are level 18 on our 2-year campaign. I am in the process of writing a story where they will switch souls. After that campaign, I thought of rewarding all of them with a 1-level dip in any other class. However, I don't want them to be kept from reaching level 20, so I want this dip not to give them that drawback.

Are there any large issues with just giving the players the regular features from that 1-level dip, and then progressing with the remaining class up to level 20?

One hitch I have at least found is spell slots. I'm not sure how to build spell slots for the 21st level up (when the characters are 20/1).

---

Example: Our 18 Ranger will most surely make a 1-level dip in Rogue, for level 1 Sneak Attack. But he still wants to have the level 20 Foe Slayer Ranger feature in the future.

Our 18 Bard can pick up Cleric for proficiency with Heavy Armor using the Life Domain, but she doesn't want to miss out on her Superior Inspiration after 2 more levels.

---

This being a homebrew kind of question, feel free to ask for more information if I have not been clear on some point.

Answer 1

As I see it, you have two choices:

Epic Boons

This is the default and official (though optional) way to make characters go beyond level 20. You can give them all skill proficiencies, extra level-9 spell slots, have them bypass damage resistance... In general, they are (very) buffed up feats that the DM may award. While officially you are only supposed to give them post-20 I don't think giving them at 18 would be too game-breaking (take this with a grain of salt, some boons are really powerful, specially some homebrewed ones).

This has a downside, however: You can't grant an epic boon more than once (with few exceptions). Which means that you won't turn out with characters as powerful as they would be if you just granted them extra features. Not saying this is bad, just pointing out that this would be giving your characters powers they would "normally" gain post-20 a bit earlier, and nothing more. If you want to continue a post-20 campaign, you'll run out of relevant epic boons to give at one sooner or later.

Level 21

A bit concerning balance-wise, but a viable (homebrewed) option. A level 21 character would have level 20 in a class an level 1 in another (or any other combination through multiclassing).

The two main concerns are :

• Spell Slots: Looking at the table for Multiclass Spellcasters - Spell Slots per Level, the next logical step for level 21 would be an extra lvl 8 slot (since you gain extra level 5 at 18, extra level 6 at 19 and extra level 7 at 20). Powerful, but the Boon of high magic gives you an extra level 9, so not too game-breaking.

• Proficiency bonus: Looking at proficiency bonuses they increase once every 4 levels, so a level 21 character would have +7. Really powerful, and breaking a bit the bounded accuracy design of 5e... But at high levels of play it shouldn't be too game-breaking (I made similar houserules for over-the-limit levels of play in other systems, and they can be fun if your players like it). If you think this is too much let the Proficiency bonus remain at 6, but I'd go to seven. If we're making extreme characters, let's really go for it. Also, it makes more sense to continue the progression.

The rest.. well, just a level as usual. Extra hit-dice, class features... Nothing out of the ordinary here.

---

I personally think the choice should be up to you. The level 21 option is quite powerful, but if that's what you're aiming for it's the natural way to progress, in my opinion (and top level play in D&D is over-the-top already, so why not turn it up to eleven, or twenty-one?). If you want challenges to remain... challenging, just start giving epic boons two levels early.

Answer 2

What problem do you have with the existing rules for giving things to epic characters?

There are three rules legal ways to reward level 20 characters.

First, you can give more loot. If they aren't using all of their attunement slots, give them more attuneable magic items. If they are using all of the slots, then give them another anyway, and force an interesting decision. If your players are interested, consider including them in making a custom magic item per the creation rules in the DMG.

Second, in the DMG starting on page 227 is a section on Supernatural Gifts. This covers minor and/or temporary benefits. Options include limited casting of some spells, stat boost/max stat increase, and permanent advantage vs. magic. Later in this section is the subsection Training, which grants things like a skill proficiency or feat.

Third, in the DMG starting on page 230 is the section on Epic Boons. Less powerful than a full level, but still thematic, it provides options like "one extra level 9 spell slot", "one level 1 spell becomes an at-will use power", "your walking speed increases by 30 feet".

---

To address the specific requests of those players:

A good option for your bard is to grant each player either a Feat from section two above. This would easily cover cases like "I want heavy armor".

Totally off the rails, rules-wise, is picking apart classes and giving one small part (like sneak attack) to a player, without giving the rest of the class (hit die, proficiency bonus, etc.). Consider using option 1 above, and giving an item that grants something like that.

Answer 3

As I understand it, you want the 1-level dip to represent the time they spend experiencing another class whilst they were switched. Am I also correct in saying that the players don't necessarily want a 1-level dip specifically, but rather you think it would be cool to have them all have something permanent to represent that time spent as another class?

In which case, the DMG (pg 227-8) says awarding feats can be an acceptable reward for DMs to hand out to players, in this case they can just be custom feats based on class features rather than the normal feats (although for spellcasters, you can literally just give them Magic Initiate). That would carry the "flavour" of having some leftover skills they picked up, but without messing with the leveling system.

See this answer for more info on handing out feats as rewards.