Dungeons 3

This is done in the "The Prince of Hell" level. The level has a sacrificial pit that the game tells you to find ingredients to feed into to summon a Pit Fiend. However you can throw other things inside it for interesting effects and bonuses. There are 3 bonus creatures that can be granted by the pit and you need to sacrifice them to get all 3 for the trophy:

o 5 Rogues - 1 Arachnid.
o 5 Wardens - 2 Imps.
o 5 Novices - 1 Succubus.

Higher levels of these Hero types have different names e.g. Thieves are upgraded versions of Rogues. To see the list of names of upgraded Hero types, refer to the Almanac from so e.g. Rogues, Assassins and Thieves are the same type of Hero and count towards the trophy.

You don't have to feed all 5 at one go, just 5 cumulative over time to unlock each bonus creature. However depending on your luck (since invaders spawn random types of Heroes), you may not get the necessary 5 of the same Hero type. Sadly you just have to keep playing and hope for the right ones to spawn. Once you've dropped all 15 of the required Heroes and have all 3 bonus creatures come out of the pit, you'll have your trophy.