Why kill what you can claim? Enslave Mind is a Level 6 Thaumaturgy that requires 4 to cast. If it gets through the target's Magic Resistance, the target is Enslaved; they don't get the Slave status, but they're reduced to a lowly unit in your army.

Enslaved Commanders lose their Commander status, along with their magical knowledge and Items. If elevated with Gift of Reason or Divine Name, their magic levels are reset to defaults, re-rolling random paths and whatnot.

Are Hall of Fame stars lost?

Enslaving a specific target can be tough in the heat of battle, but there's Master Enslave for that; it's a Level 9 Thaumaturgy that requires 8 to cast and consumes 8 on use. Master Enslave attempts to Enslave the entire enemy army, in one fell swoop; it's not incredibly thorough, however, for the base MR Penetration is a measly 7 instead of Enslave Mind's 11. It also accrues a whopping 800 Fatigue, so it'll do around 24 HP damage to the caster without Communion support; you wouldn't want to trade your one-of-a-kind Astral god for a bunch of chaff, would you?