Cremation's name is Conjectural. No official name has been given, and it is subject to change at any time.
Like Hellflame, Dabi's Quirk grants him pyrokinetic abilities. Dabi's flames are blue in color, and he's capable of generating and manipulating them at will.
The user can ignite blue fire anywhere on their body with minimal effort or movement almost instantaneously. They can also combust anything they touch almost instantly, including robust minerals and living creatures alike. For example, by touching a single tree in the Beast's Forest, Dabi was able to set the majority of the forest ablaze, trapping everyone there in a ring of fire.
The flames are extremely hot and it is believed their temperature is higher than that of normal fire, which is signified by its blue color. Dabi's flames were hot enough to burn an entire group of villains into ash in mere seconds.
The major drawback of Dabi's ability is that his body can't handle the heat. Overusing his flames will cause his skin to swell and slowly burn over time.
Dabi primarily uses his Quirk to fight from a distance and burn his enemies using fireballs and flamethrowers. He can also release a short burst of flames for roasting his targets at close range. Dabi often relies on the brute force of his powerful Quirk to overwhelm his enemies. His fire blasts are powerful enough to collapse building walls  and were enough to completely repel Snatch's Quirk. 
Dabi also uses his Quirk tactfully, creating walls of fire to trap his targets within a fixed area. This Quirk also combos well with Compress, as anyone compressed along with some of Dabi's flames will burn to death. 
- Although unofficial, "Cremation" is a popularly speculated name. It is drawn from Dabi's name, which is translated directly as "cremation."