The Axe is a melee weapon in Doom RPG. It does not use ammo and in addition to being usable as a weapon it can also be used to break down beaten-up doors. It is suitable for melee combat against zombies, implings, archviles, or any weak enemy.
Zombies are particularly weak against the axe, so it is a good choice of weapon to use against them. However, as a melee weapon this requires moving into close range of the enemy, increasing the probability of sustaining damage.
On the ground, the sprite for the axe appears to be sideways on the axe head, as if the axe was struck into the floor. Also, in a terminal in Junction, 2 Fragments of an ABC poem are readable, one about the axe: A is for Axe, crashes like thunder. Z is for zombies, rend them asunder.