Normal: "A fiend blazing with the power of fire. If it gets knocked around too much, the flames smoldering within cause it to explode." Oversoul: "A fiend blazing with the power of fire. If it gets knocked around too much, the flames smoldering within cause it to explode." — Scan
It is recommended to take them out in one hit, or knock them down to about 1/4 of their max HP and then try to kill them in one go to avoid their explosion attacks, though having Fire-resistant equipment or abilities will help nullify that. In Oversoul, it is best to take them out as fast as possible. Using Black Sky, Flare, Ultima, or high-powered physical attacks works well against them.
In the Fiend Tale endings, a notable Volcano escaped the capture of his kin by members of the Order of Yevon who intended to develop weapons from them. With the Gullwings' help, Volcano reaches Bevelle's underground where the experiments took place and uses his Self-Destruct to kill the Yevon scientists.