The Lockwarden

"'Look - let's be real. Wearing slick, black, gold-trimmed Allarus Terminator armor is just as erogenous as wearing - nothing at all.😎'"The Lockwarden is the shield-captain of the Shadowkeepers of the Adeptus Custodes.

TTS Canon
As the Shield-Captain of the Shadowkeepers, the Lockwarden's duty is to keep the ancient and forbidden technology (such as a Billy Bass covered in a mass of mechadendrites) hidden beneath the Imperial Palace from ever escaping. In the past, Kitten had apparently last visited the vaults for solace after his breakup with Commander Shadowsun. Kitten is very keen to prevent the Lockwarden from ever bringing up the incident. The Lockwarden, while still wearing his full armor, considers it to be comparable to complete nakedness. He sometimes ends his sentences with a smiley face with sunglasses emoji

Kitten gathered the Lockwarden and his Shadowkeepers to help guide the Mars Delegation on the datascapes of Mars. After engaging in some banter, where he identifies gold-black terminator armor as being just as erogenous as being naked as The Fabulous Custodes, and feels honored at Santodes' venerable presence, the delegation is teleported to the Red Planet.

Reaching the Fabricator-General of Mars, Lockwarden added his deep baritone to the choir of Custodes to convince the Mechanicus Lord to hand over the Proteus Protocol, even holding up an astropath to give The Emperor a call if he needed further proof that they were on a mission from Him on Earth. After being successful in this argument, the Lockwarden shares his comrades' sentiments that, despite their teasing, Kitten is the perfect Captain-General to lead the Custodes. The delegation them departs for the Noctis Labyrinth to retrieve the protocol.