Bandos gets a moment of awesome in possessing Zanik for the first time to kill Sigmund.
It becomes more awesome in hindsight when a tier list was made to show the power of each god. Bandos was up in the tier with Saradomin and Zamorak, two of the key gods in Gielinor's lore, before getting dropped into the next one due to the player's interference. It wasn't just screwing over Bandos' plans, but severely weakening him as well.
The end of the Legends Quest. For reference, the player just defeated Nezikchened, a powerful demon who put a curse on the Kharazi Jungle. Nezikchened swears that he will return, more powerful than ever. Your response?
Although it happens after Guthix's death, watching Saradominfail to teleport you, demonstrating your new anti-god ability was very awesome at the end of The World Wakes.
More impressive in that the teleportation spell flawlessly whisked Nex, Char, and several renewed strong Mahjarrat. Saradomin has good reason to be surprised.
Also, the player, should they chose to do so, manages to motivate the Guardians of Guthix to fight against what seem to be impossible odds.
When players first logged on after the Runescape 3 update, they were met with a cutscene showing Zamorak and Saradomin meeting outside Lumbridge, and engaging in a Beam-O-War. It caused the area between Lumbridge and Draynor to turn into a blasted battleground, with glowing green rocks everywhere. This was the setup for the first World Event; players can choose to fight for Saradomin or Zamorak, gathering as many of the green rocks, or "Divine Tears" as possible to empower their chosen god and help them overpower the other.