Thanks.
I don't know that much about modding though. It sounded so easy but there so much details to it. I'm only getting to the point where I have one unit conferring insane horror mark levels and make horror weapons insanely strong.
Maybe someone can help me:
(newspell) Copy the spell Manifestation and let it summon a
(newunit) horror mark remover 1
no attacks or anything just
summons in battle (like moloch summons imps)
(newunit) 15 horror mark removers 2 (did that)
these have 2 horror mark attacks (like the doom horror) with 100 attacks per turn that always hit (I suppose they do anyway) and 1 with 57 attacks
Make them unhitable by normal weapons (very high def, prot, awe, etc) but die after 17 rounds...
(newspell) maybe autospell poison damage on them
Make some flavor text about this ancient ritual and the terrible risk involved (in case something goes wrong) - instadeath by doom horror.
I remember something in there is impossible (summon new unit or autocast new spell but maybe you could change old units/spells for that)
You get 17*15*257 = 65535 horror marks in an assassination battle that targets horror marked units. That means you remove 1 level of horror marking. Cast it on a horror marked SC repeatedly until horror mark is gone.
P.S.: Don't tell me I'm mad I know that anyway.