Necromancer's Abyss
Trial: Finish the level after destroying 60 reapers.
There are 56 Reapers on this stage. The last 4 you can get from the 2nd Necromancer. He will summon Reapers and Zombies. Depending on how many you killed up to that point, you will need him to spawn them and then kill them. It appears when he spawns them and pulls them back it counts towards your totals unless 2 of my kills were delayed.
The Dracolich
Trial: Finish the level and defeat the Dracolich in 5 minutes.
Much like the other Titan bosses you will require a Dark Crystal for this. Use it immediately and wait for the opportunity to grapple the boss. The time should start when you. You want to destroy the Chest rune by 1:20-1:30 left. The cutscene after takes up about 30 seconds and cannot be skipped as there is a QTE event. Also watch for the wing bones. If you jump when they are too far apart, you will fall. You basically have to do this in one run. If you fail after the first rune just head back to the world map and restart the level as the Autosave doesnt help.