Hell, the opening of Horus Rising is one.Nero Vipus slices off his arm after it was injured saying that he 'threw it away'.Tarvitz accidentally destroys the source of the transmission jammer when he uses explosives on trees because he didn't like the way the bodies of soldiers were hanging on them. Saul Tarvitz (who eventually befriends Loken) survives an attack by bladed-spiders and vicious birds.Iacton Qruze (yes he was treated like a doddering old fool of a Space Marine) was actually a lot smarter than he looked and on his own managed to break the back of a megarachnid attack wave.Also, during heavy combat with the Megarachnids, Lucius picks up a limb of one of the fallen, and uses it as a weapon. Lucius challenges Loken to a rematch in the next book, and wins. Which is not to say that Lucius doesn't have his moments.Loken beats him by grabbing his sword hand and punching him to the floor.

Whilst in a sparring match with a Lucius (the best swordsman of the Emperor's Children).Even after beating Jubal, Loken tries to keep him alive until he is finally forced to kill him.

Right after he gets up, Jubal draws his knife. So he does the next best thing: he wrestles the gun out of Jubal's hands and nearly gets thrown off a cliff. One memorable moment: After one of his Astartes Xavyer Jubal is possessed by a daemon and kills another Space Marine (which is a cardinal sin, by the way), what can Loken do? He can't shoot Jubal, as that would be breaking the laws of the Imperium and the bonds between the Astartes.

Loken himself is just full of awesome.

But Loken rebuts his argument perfectly by pointing out that the Imperium had before tried opening diplomatic channels with the planet instead, and the 'Emperor' had responded by murdering their ambassadors. After killing tons of invisible baddies, he meets the 'false Emperor' who proclaims that the Imperium is wrong in its doings.

The opening book, Dan Abnett's Horus Rising has Garviel Loken rush in and avenge his senior commander Sejanus.

Horus heresy tv tropes