The spell Animate Dead has gone through many changes. They are detailed below.
An undead creature will join your party as henchman until destroyed. If cast on a player corpse of a player that is online at the casting time, the power of the creature will depend on level and class of the deceased. If you have spell focus necromancy, the creature created will be a duplicate of the PC you animated, but undead, complete with equipment, feats, skills, and spells. While animated, the PC cannot be raised or respawn. A True Ressurrection cast on the PC will destroy the summon. Additionnaly, animating a corpse dispels invisibility on the caster. It is possible to have many undead minions at the same time.
Animate Dead takes advantage of the Reagent System to summon new types of undead. There are many, so experiment in game to find them all.
Animated dead can now be left behind using a dot command .staydead They will be removed from your party and then essentially be monsters like the random spawns you find around the server.