Napalm Man is a brandished user of explosives built by Dr. Wily. Purpose: Destroy! Burn everything to the ground! (Including Mega Man).
In the events of Mega Man 5, Napalm Man had snapped completely when he was fed chili peppers from the Dark Men. Thus, he went on a rampage in what was thought to be an old Vietnamese jungle. Mega Man had defeated him simply - shooting him until he somehow hit the heavily guarded off switch.
Only months later, in Mega Man IV (GAMEBOY, not NES) the explosive war machine was paid very many Bolts from Ballade to guard the Wily Tank's four WILY Tokens. However, after the incident he shares a deep rivalry with Ballade for having a better explosive weapon.
In a recent drawing of Robot Masters, Napalm Man was chosen as the representative for Mega Man 5, and his data was implanted into the second Weapons Archive. He now constantly battles Commando Man because, when Napalm plants mines, Commando makes them all explode. Get the picture?
Between 20XX and 21XX, after Capcom's last classic-series game, Napalm Man had sorrowfully exploded for the last time. One of his partners, a (revived) Grenade Man accidentally stepped on Napalm's OWN LAND MINE, and they both were caught in the explosion. While Grenade Man had suitable fragments of armor for a revival, there was no trace of Napalm Man found ever again.
"MWAHAHHAHA BURN BURN EVERYTHING TO THE GROUND" (Playing Call of Duty 4
"Oh, hello." (5 seconds after Megaman enters his boss room while he plays Call of Duty 4)