MTL is Merrell's mountain race line and the Skyfire 2 is the sharp end of it, built for the athletes Merrell sends up mountains. A 25 mm heel puts you close to the ground, deep Vibram MegaGrip lugs hold on steep dirt, and a FlexPlate sits between your foot and the rock so the shoe protects without going stiff.
It suits you if you race short and steep, or if you train on ground that is genuinely technical and you would rather feel what you are standing on than float over it. The upper is cut thin and breathable to match.
It is not a long-day shoe for most runners. There is very little foam under you, an hour of gravel road will remind you of that, and the shallow stack that makes it precise on rock leaves nothing in reserve late in a long race.