Hexenjaeger: Nice to hear! There are some really cool witch hunters based on 40k cultists. Including your conversion!
Very epic can i ask how did yo paint the Armour for you're knights i would like to paint my new knights with the same dark steel look but i have no idea how?
First of all, I find painting metals hard. It never turns out quite the way you'd expect it to.
Here's how you do it. Might sound hard but it is actually rather fast if you paint the metal parts for a whole unit. I'd say painting 14 knights the stages 5-10 took maybe a bit more than an hour.
1) Black basecoat (even though I spray my troops with Army painter Uniform gray)
2) Boltgun metal (or the darker Citadel metal paint)
3) Wash with Nuln oil and some parts with brown ink
4) Highlights with Mithril silver (edges of weapons&armour, some battle damage etc.)
-- before the next steps I paint the whole model ready because it is not fun to paint over weathering powder. I've never actually tried to paint over 'ardcoat but I suppose there is no problem doing so?--
5) Wash the whole metal parts with black weathering powder mixed with really cheap Russian vodka.
6) When it's dry I use my thumb/large brush to take off most of the powder
7) Rust effects to some parts with brown weathering powder
8) I usually leave most of the brown stuff. But you see what looks good when it's dry.
9) Another highlights with Mithril silver if needed. It is annoying to paint over weathering powder.
10) Hardcoat. This is really important when using powders.
Sometimes I also add the turquoise effect on top of silver coloured metals. See the result on the witch hunter's pistol. I'm happy with how that pistol turned out but seriously it was really easy to paint. Basically one layer of metal + wash + highlights + powder.