If a Champion is killed, their "gold amount" is added to the loot of the victor.
(if a dragon killed a group of heroes, the heroes' gold amounts are added to the loot of the dragon)
(In a Faction vs Faction battle, the gold amounts of slain heroes are added to the battle loot)
A resurrected Hero (from resurrection spell) starts with a 0 gold amount and gains 1 gold per turn until they reach their "default" gold amount.
A reanimated (undead) Hero always has a 0 gold amount.
If one of your own Champions dies in battle, (and you win), the gold goes to their families (not to you).