Level: Zarok's Lair

During the final level, in the first encounter some enemy soldiers will spawn on the opposing side and on your side some skeletons will spawn. You get a new "weapon" called "Good Lightning" that trades your health vials to buff your troops. It is your job to keep your troops alive.

For this trophy, "giving them everything you have" means healing down to your last health vial. For me it unlocked when sacrificing 4 of my health bars to my troops via the Good Lightning. You must continuously hold down Square with the healing chalice equipped and run left and right in the middle land (between the troops) so the green lightning hits your friendly soldiers. It's enough for the green lightning to hit them for a second, then move on. The lightning will always hit the nearest skeleton, no need to aim it. Don't stop walking, stay in constant motion running back and forth. It will unlock immediately during the skeleton fight even before this fight is done!

If it hasn't unlocked by the time the skeleton fight is over, restart the level immediately and retry. Make sure you got at least 3 full health vials above your health bar before you start.

Note: it is NOT necessary to have collected all Chalices or Souls! You can do it without having collected either of those.