User blog comment:DirgeOfCerberus111/Adeptus Custodes Vs. Grey Knights/@comment-33731050-20150327035801/@comment-2253300-20150327080132

Actually the custodes took part in the Burning of Prospero. Big E sent them alongside Russ to bring Magnus back for judgement. aside from that they also took part in the Battle of Terra naturally. The last recorded mention of them ffighting to my knowledge was on Pluto. The Lords of Decay CSMs luached an attack on Pluto, the first battle in the Sol Systemsince the end of the Horus Heresy. A squad of Custodes were sent in the force to deal with the attack. However they were killed by a Champion of Nurgle, who was then killed by Grey Knights.