I've been playing Black Crusade for a while, and just finished making my daemonic legacy weapon.

Currently it 1 shots everything the GM throws at us, because anything stronger 1 shots every member of the party.

Name: Best Quality Legacy Daemonic Multi-Melta "Utter Annihilation"

Class: Heavy RoF: S/2/-

Range: 60m Penetration: 17

Damage: 3d10d1+21 Special: Melta, Blast(1), Hatred on 1s, Crippling(3), WP test if not firing burst, Vicious

And I wondered if anyone else had a ludicrously strong weapon.

nuclear bombs and a ritual that blows away the atmosphere from a planet.... stats for damaging was unnecessary....

Rift breaker - Legendary artifact force sword.

In addition to the standard damage for a master crafted force sword it had 10 charges which slowly regenerate. Use one charge to create a gate of infinity. Expend four charges to cast vortex of doom centered on impact point in lieu of force weapon damage which didn't affect the user immediately. Chance to suck an enemy into the warp on hit. Yep.

Demon Weapon Tachyon Arrow.

OH yes my GM made this for my last black crusade character killed a greater demon without much issue

Ranged Weapon – Trusty Legion Reaper Autocannon, Good Craftsmanship [Heavy; 300m; S/4/-; 3D10+8 I; 6; 50; 2 Full; Reliable, Twin-Linked; 60Kg]

Conventional Upgrades

Extended Magazine: 25% percent bonus clip size

Melee Attachment: [Melee; 1D10+2+SB (8) R; 2]

Red-Dot Laser Sight: +10% to Ballistic Skill when fired on single shot

Spread Limiter: Every two hits upon Semi Auto roll for one Hit Location.

Legacy Weapon – Legacy of Pain – Bellicose Pattern

Adds one half Infamy Bonus (rounded up) to both Damage and Penetration

Crippling (1) Quality

Shattering: Razor Sharp Quality

Nice weapons, let me see what the stock standard Nova Cannon attached to the front of this Battlecruiser has to say about it.

I made a "Black Pack" from the show Lexx as an ancient xeno weapon. It was in severely poor condition when found, and eventually exploded from use. These were the rules I gave it

Ancient Xeno Hand Weapon ("Black Pack"): Pistol, 30m, S/-/-, 3d10+10E, Pen 10, 6 Shots, Reload - (recharged on the ship during narrative time), and the Vaporization rule (any critical damage causes immediate death)

It had additional custom rules. It could not equip any weapon upgrade or modification. Furthermore, if it jammed, it would explode within 1d5 rounds, doing 3d10+10E damage, Pen 10, Vaporization, in a blast radius of 5 for every charge not yet fired. A roll of 100 results in instant explosion. Oh, and the weapon was immune to fate, meaning fate points could not be used with it (meaning no re-rolls if it rolled to explode).

Our kroot was the only one ballsy enough to use it. It finally rolled to explode while he was fighting a daemon engine. He threw the thing at it when it started to hum ominously and overcharge itself, and completely vaporized the daemon cyber-beast's front foot before escaping.