Eiku Shizuma (閑馬永空, Shizuma Eiku) was an early member of the Itto-Ryu and the first immortal antagonist in Blade of the Immortal.
Shizuma was given the kessen-chu much like Manji. However, unlike the recently immortal Manji, Shizuma had been immortal for nearly two-hundred years, learning of powerful poison that prevents them from regenerating the wounds in the body. He covered both of his weapons in this poison and use to fight other immortals. He has an aspiration for taking over the world finding Manji a possible ally but was quite disappointed when this was not the case. As with other immortals, Shizuma lacks the fighting style of normal human not even flinching at pain or trying to dodge attacks his very immortality becomes his weakness, one that Manji fears will weaken his own swordsmanship. In the end, Shizuma was killed by decapitation and the same worm-poison which slowly took effect showing just how strong the kessen-chu could be. While the poison he uses is never given a proper name other than 'Wormkiller' it’s later used by Fujiaki Kasori in an attempt to kill Manji.
- Damn right!! With these eyes... I've seen the dynasties fall!
- Maybe you could call it satori. One day I realized that... all I had really needed, all along, were people just like me.
- It's true... living like... like a worm... ...one...tires of it.