This is shishio preparing to use his Tsu no Hiken, Kaguzuchi, an attack where fire surrounds his sword.

This is Kenshin's sword clashing with Shishio's. The swords clash with such strength, that it litterally creates a void

this is another shot of Shishio's Tsu no Hiken. Lemmie explain it a bit more - Shishio is so evil that his Kenki (or ki for short, all you DBZ hot-heads) that it can litterally manipulate fire. Here, he holds his sword (kitana?) above his head and manipulates the 'embers of hell' to fly around him.

Here, Kenshin gathers more energy for his void, causing it to grow bigger, and stronger.

Here, Kenshin's Kenki has become so great, that he litterally breaks the earth as he walks.

Here, Shishio surpasses his limits, and becomes much stronger...

Note, that isn't Ki surrounding him, it's blood. His Kenki is so great and strong, that his blood is litterally evaporating out of him. This is why I say they cannot show kenshin without edits.

Speaking of edits, here is a scene that is DEFINATLY gonna get edited.