The Souledge is the weapon of Tye The Hedgehog in both series.
In its sealed form, it takes the form of a sword that slowly devours the opponent's soul upon contact. The weapon in its awakened form takes the form of a scythe with a Electric energy blade that seems to be made out of souls.The Blade can take on three forms you already know the first two. But it can also change into a gun.
Tye uses the sword form most often which allows him to gain quick attacks with his blade. The scythe form allows Tye to attack mid-ranged which Is used to his advantage and his Gun form allows him to use long ranged attacks and ready for instant blast. Tye uses the scythe form when he activates it. It really increases his attacks by alot. Though It looks like a sword and not a scythe it can drain your energy every time it hits you. So the sword is basically like a person.
Tye The Hedgehog
Sonic allstars EX series
Tye is the one and only user of Souledge. Though it's like the other sacred weapons, He the only one who can wield it. Thanks to Tye's Demonic Arm he is able to control the power that resides in the sword. He was told "Don't think that this sword is only yours, Use it wisely" by his master and friend Hector The Echidna.
In the main series Tye has got it in another way.One day he got the sword while he was sent to retrieve it. It was guarded but he managed to defeat the guardian. He grabs the sword but nothing happened. It didn't only bonded with him but enhanced his power too.
The name applies to the blade itself, Soul-Edge. So when used in combat you are able to drain your opponents life force from them and use it as your own. Though it sometimes drains some of your own in gun mode. In Sycthe mode , when attacking you would see some crimson like energy coming from it meaning the attacks are stronger.
There was gonna be a point in time that Tye would receive the weapon.
The blade was created along with the rest of the sacred swords. The blade was at first concealed in darkness while the rest were split up. One is currently carried by Rin who caries Frostbite.
Longtime ago there were a prophecy. On it It stated there was a sword that no man could and soon enough a new evil was rising. So they decided to split the sword into seven different parts. Faust,Xernos,Zeros,Fleshrender,Justice,Valkyrie,and Storm Breaker. Two more were made after the original seven were created. After the Great War the owner of Xernos overused its power and lost his soul to it giving it the nickname Souledge. So anyone who got their hands on it got their soul's taken along with.
In the Hands of Tye
So one day Tye managed to get his hands on it without getting his soul taken. He thought it was a normal sword but to he felt some kind of power residing in it. Once he took it out of its place it started to glow red and then his arm started glow too. It automatically bonded with him and from that moment he knew how to use the sword. He didn't need any training or special requirements either.