To get Anubis Axe in King Legacy, you must defeat the boss Anubis (Level 3150) at Dead Tundra in the Second Sea. While the quest to defeat Anubis has a level requirement of 3125, there is no requirement to fight the boss and obtain the drop. Anubis Axe is an Epic Sword, so its drop rate should be around 1%.
Anubis Axe is one of the tier-A swords in King Legacy, as it is quite accessible, effortless to use and good for DPS. Its M1 attack speed is slow, and it deals 3,826 damage with Armament Haki V1. Anubis Axe is definitely not recommended in PvP as both skills deal a single blow. Their damage is quite heavy, and they are both easy to use, so it's a good sword/axe to use in PvE, although God Justice is a somewhat annoying move as you must keep the enemy within its area of effect.
Its Z key move, “Against God” is unlocked at 50 Sword Stat Points, and it deals 8,565 damage with Armament Haki in a single blow. This is a very easy move to use with very good range.
Its X key move, “God Justice” is unlocked at 300 Sword Stat Points, and it deals one hit for 11,251 damage with Armament Haki. It's easy to target as it just creates a circle that keeps expanding wherever you point your mouse cursor. The circle explodes once it reaches max size and your goal is to keep the mob in it.
Note that you must have Armament Haki enabled for both Skills to work on Logia users.
Overall, while this a useful weapon that looks really cool, it's also a weapon that you will replace really fast in the Second Sea.