Alter of Skulls works better for the necromancer because he can defend one conjuration better than two, and if he keeps Mort with the alter, you can heal it and Life Bond +2 means the Necromancer gets to heal up to two damage while the opponent cannot heal and gets damaged 2 damage (3 with IoP). One of my favorite Necromancer strategies.
His Lifebond is better than the Druids, because Mort can reconstruct (heal) even in finite life conditions.