Kireek

[K_I_R_E_E_K]

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He had a rival on Pioneer 1. To obtain his Soul Eater, you fight him in "From the Depths" after he defeats Ash in the ruins. If you defeat him, he will drop his weapon. After he is defeated by you, Falz takes his nearly dead body and he meets the same fate as everyone from Pioneer 1.

Kireeks' P1 rival was HeathCliff Flowen. When Kireek learns that Flowen Died, he tries to fill the emptiness by doing Black Paper's dirty work, becoming the Assassin "The Black Hound". However, no one seems strong enough to truly challenge him as Flowen once did, so he challenges you instead, after he dissappears once the authorities begin an investigation. "It is rumored that he was killed by a hunter, but the rumors are unconfirmed".

he becomes crazy because Falz does his work, he sees the potential in this char and uses him to make some stuff, like kill you.
if you play from the depts you see that whenever the white fog comes (falz) everyone starts to act crazy in a uncontroled kind of way, same happens to KIREEK.