Make a high level wizard that behaves as a low level wizard
There is one characteristic about wizard that are common through every D&D game, they are extremely squishy, especially if they are badly built or they used all their spells before a fight. A wizard without spells is not different than a level 1 fighter with more hp, maybe better to hit chance and, probably, worse AC. Another thing, by RAW the spell Animate Dead and Create undead apply a spell slot tax to maintain the the undead horde, this will reduce the number of spells that the wizard may cast.
Animate Dead: To maintain control of the creature for another 24 hours, you must cast this spell on the creature again before the current 24-hour period ends.
There are some consideration to have so the “high level” wizard maintain a reasonable challenge rating. There are 3 particular things to look for; cantrips, intelligence and spell slots, and proficiency bonus.
In this edition all attack cantrips rise in power as the wizard increase in levels, but it is done at specific levels: at 5, 11 and 17. The minimum level of the wizard is 5, since Animate Dead is a level 3 spell, therefore one possible level to keep it as low as possible is 10 or at most 16.
Firebolt: This spell’s damage increases by 1D10 when you reach 5th level (2D10), 11th level (3D10), and 17th level (4D10)
Intelligence and spell slots
In 5e intelligence does not increase the number of spell slots that a wizard may have and the cap for each spell level is achieve quite fast. For example, at level 4 the maximum spell slot for level 1 and 2 spells are reached, and at level 6 level 3 spells are maxed out (Table on PHB 113). This implies that increasing intelligence will not impact the spell progression, only the chance to hit with spells, DC and INT related saves and skills. A well built Wizard would have INT capped at level 8.
To make it short, the relevant capstone for proficiency bonus are 9 and 13 since 5 is absolutely necessary for Animate Dead by RAW.
Wizard apparent level
Aside for HP and the capstone discussed previously, what really limits the apparent level of the wizard is the spell at his disposal. An example on a level 6 wizard, If we use every single third level spell slot we can have 12 zombies, four for each third level spell slot, the apparent level would be 4. Yes, bounded accuracy is a thing in this edition, but depending on the spells this might not even matter (e.g. Magic Missile: no save, no DC and not miss chance)
Animate Dead: At Higher Levels. When you cast this spell using a spell slot of 4th level or higher, you animate or reassert
control over two additional undead creatures for each slot level above
Magic Missile: You create three glowing darts of magical force. Each dart hits a creature of your choice that you can see within
Number of undead by capstone
Since the objective is to have the maximum number of undeads while keeping a low apparent level as possible, all high level spell slots are used to cast animate dead:
- At Level 7 (pre ASI): 12 + 6 = 18 (3 level 3, 1 level 4)
- At Level 8 (pre proficiency bonus): 12 + 12 = 24 (3 level 3, 2 level 4)
- At level 10 (pre cantrip damage increase): 12 + 18 + 16 = 46 (3 level 3, 3
level 4, 2 level 5)
- At level 12 (pre proficiency bonus): 12 + 18 + 16 + 10 = 56 (3 level 3, 3 level 4, 2 level 5, 1 level 6)
At level 10, the wizard is capable of keeping 46 undead under his command by RAW, while maintaining the same spells as a level 4 wizard. An example of a hampered wizard would be:
Half elf level 10 Wizard (Average HP: 32 (6 + 36 – 10 (-1 con))
- STR: 9
- DEX: 12 (11+1)
- CON: 8
- INT: 20 (15 + 1 + 4)
- WIS: 14
- CHA: 16 (14 + 2)
This would yield a +2 DC and hit over a level 5 wizard with the same INT progression, and the same 32 HP that a level 3 Fighter with CON 14 would have. Nothing impressive if you ask me (aside for the sheer number of undeads).
- Multiclass: If you multiclass with, for example, a Death Domain Cleric, it won’t hamper the spell slot progression but it will diminish some benefits of the level 6 and a 10 wizard schools capstone. This even apply a little MAD and would be thematically relevant. It would gain more HP and a better AC with armor, this might be good since it would not be so squishy.
- More squishy wizards more undeads: 4 wizards can control almost 200 undeads and they don’t need to fight the party at the same time.
- Keep calm, build them bad: The more you mess with the built, the weaker and more challenge appropriate it will be. “Bad” choices would make some good RP elements (mistakes happen to everyone, maybe a level in sorcerer was not his best idea).