Jalhalla is, together with Molgera, one of Ganondorf's two guards for the power of the sages that can restore the Master Sword. Jalhalla is found deep into the Earth Temple and he is the leader of all poes. Jalhalla guards the power from the Earth Sage Laruto, who he killed ages before this day when Ganondorf decided to weaken the Master Sword. Jalhalla is, in truth, only a mask who uses the power of 15 poes within him.
Jalhalla's chamber is pretty much his fate, and what you use to destroy him. The fight is built up with two phases that repeats themselves after each other and the minimum amount of cycles are three. Your first move is to stun him with the use of the dungeon item, the mirror shield. This is done by aiming towards him underneath a beam of light. There are three beams in the chamber, but they all randomly fades out which might mean that you will have to find an other beam while aiming. After you have stunned him, he sits on the ground and you can run towards him, pick him up and throw him towards the spiky pillars at the wall. This splits him up into 15 smaller poes.
After he has been split up, you have to kill all the poes one after each other. Although, as written earlier, the minimum amount of cycles are 3. At each cycle you can kill the maximum of 5 poes before Jalhalla spawns back to his original essence. The easiest way of killing all the poes are slashing them with your sword with the double damage from elixir soup. If you take too long before killing 5 poes, Jalhalla will spawn back after 15 seconds and one extra cycle will be a fact.
With a good aim, arrows can be used to kill the poes in the second phase. This doesn't necessary save time though, unless you are very fast with your aiming. It takes two arrows to kill one poe. The interesting thing though is that because of the mechanics of the arrows you can hit multiple amount of poes in one shot if they are lined behind each other.
Because of the fact that you need to lift Jalhalla from the ground to split him up, the power bracelets can not be skipped in a low% run. This is the one and only barrier where the item is really needed to continue.