How do I even find a cave troll?
They’re more likely to be in the bottom half of the world crust, so explore the deeper caves, and you should find them.
By the killer red stuff?
I always dig a two block tunnel around the bottom of the world just above where the heat from the lava starts to injure you and explore the caves I find there. Just keep exploring you’ll find one
No, you don’t have to go down to the level where the core heat harms your Blockheads. I’m talking about below halfway between the surface and the core. That’s a huge space.
It takes a lot of effort. It’s not easy at all, but I found a interesting pattern that happens on all worlds (or most of them). If you dig directly below the spawn portal, you will most likely find a cave troll there.
You mean lava?
Cabe trolls are so rare that you can find a few numbers of them near the centre of earth (100 or so blocks).