Defeating Commander Dracus has halted the Cabal push on Nessus, but Nessus is not the Vanguard's only concern. Cabal all over the Sol system have started vying for Caiatl's attention, hoping to earn a seat on her War Council. This cannot be allowed.

Osiris has devised a strategy for rebuffing the Imperial Cabal incursion without total open war. Caiatl is using an ancient Cabal tradition known as the Rite of Proving to select her War Council from Red Legion commanders to bring them back into the fold. Any challenger may approach these rites. Vanguard High Command directs Guardians to engage any and all prospective War Council appointees. With each disrupted rite, we send fractures through their empire's authority.