Undead class

You give an undead a class, it gains everything that a normal player would gain, but only half of it(I.e. they would get only 1 stat point instead of 2 stat points per ability score increase) they level up as normal, and you choose the spells that they can learn, and those spells are always prepared, but they can't learn spells from anything else (scrolls, ect). You can name these undead and re-summon them at their level by sacrificing an amount of normal undead equal to the level of the undead with a class multiplied by 2.