He finds you :)

Daisoujou: East Ikebukuro after meeting Gozu-Tennoh
Hell Biker: Highway heading to Kabukicho after beating Daisoujou

Beat the previous kalpa and get the cutscenes where all the boners r like we r the horsemen :)

White Rider: Asakusa Terminal supposedly will chase you between terminals if you warp alot idk he will show up the first time so make sure u r ready!

Red Rider: Ginza Underpass Terminal after defeating white rider.

Black Rider: 204B in the second annex building in the hospital after obelisk quest thingy and you kill the previous riders

Pale Rider: In Asakusa near the manikin collectors shop once the tunnel opens up after hearing the weird satanists reason near mantra hq

Yoyogi Park West Plaza progress locked until doing story progress in said area.

Trumpeter: Yurakucho Station should confront you after story progression

During the following phases if yu have a deathstone :)


http://www.phpsimplicity.com/heretic/

has a fusion guide tool thingy that is pretty poggers if you need to know what to combine can't link download cuz steam is cringe