To put it as short as possible, my warband it chasing down Primarch Terminator Armor and I am in need of some rules, bonuses, benefits, and any mystical-level stuff in order to help. As of right now it is planned to be armor originally forged for one of the "unnamed" Primarchs, but was never delivered to them, and was inevitably lost amidst the fringes of the Calixis Sector and thought annihilated by the Screaming Vortex upon its appearance.

I'm considering some factors, but above all, the aim is to have it be a "relic-esk magic-like" armor worthy of a grand undertaking filled with dangers, traps, and all that.

Some stuff that I've considered:

+30 Strength

+/- 20 Interaction Tests with notable Factions

Built-in Personal Force Field (60%, Overload 1 or Never)

Target only grants +10 to being hit, oppose to +30~

And so on, but plenty is spitball'd, so I call upon the powers of the community: show me what you got.

Go.

Is not Primarch in another size than an Astrates?

Beside go with a best quality Terminator armor and give it 3-4 modification....

And of course hide a secret curse in it like: " Fate of the 11th Son" or something...

Give it super awesome broken rules.

And then have it require the Size: Massive (7) Trait.

I read some were that the primarch's skin alone was as tough as power armor so they only wears real armor for cosmetic purpose...

What if the armor only a body paint?

Is not Primarch in another size than an Astrates?

Depends on the Primarch. And whether you're going by GW's Index Astartes or the new Black Library novel series.

I read some were that the primarch's skin alone was as tough as power armor so they only wears real armor for cosmetic purpose...

What if the armor only a body paint?

*snort*

Is not Primarch in another size than an Astrates?

And of course hide a secret curse in it like: " Fate of the 11th Son" or something...

Thought about the size, and considered the +10 instead of +30 to being hit if the character has Black Carapace. Also liking the curse concept, could add lots of flavour.

Give it super awesome broken rules.

Really liking this train of thought. Maybe some enhanced characteristics, or in-build relic weapons? Could go for insanity for this, if anything, to help represent the immense power of the Primarch's arsenal (armor only of course).