Sakurajima is a lava kaiju used by Mickey
Sakurajima is magma kaiju originating from deep within the earth's lithosphere. Descended from a Permian era reptilian species that escaped extinction by burrowing deep under ground and subsequently surviving off of geo thermal radiation. Eons later and metorites carrying unstable crystals originally created by space godzilla were embedded deep in the molten crust. The mutagenic quality of the crystals quickly turned One of the already mutated reptiles into a monster made of magma and ore. Shortly after the mutation, Sakurajima emerged out of the volcano of the same name and promptly went on a rampage decimating much of the city of kagoshima. Since te eruption Sakurajima has been responsible for a number of rampages at fracking and natural gas facilities world wide.
Sakurajima is made up of various types of volcanic rock making him quite durable to most forms of attack. He us also completely immune to fire or heat based attacks and due to his unique physiological make up can be healed by drinking Lava and change is apperance by absorbing different minerals in the earth's crust. In combat besides tooth and claw Sakurajima can spew fire balls or a stream of Lava.
Sakurajima is very cynical and suspicious of surface dwellers. He sees no point intervening in their petty wars unless it could benefit him or threatens his subterranean domain.