Worlds of Magic: Planar Conquest (JP)

I think this feature may be limited to the Fire plane as I have never seen it elsewhere. This world feature looks like a volcano that has blown its top and has molten lava in the middle.

In my games, even on Adept difficulty, the guardians here are pretty difficult in the early game. The Demons have a nasty spell that converts a unit into a skeleton.

Start up a game on the Fire plane with Countless Features enabled and the Cartographer, Planar Cartographer and Omniscient disciplines. With all of this you can immediately see if you can find the Hell Gateway feature.

Once you have a solid army, attack the Hell Gateway. If you win, the trophy will unlock during the battle results screen.