Use the [Seer's Crystal] at the graves of Sir Wendell Balfour, Lorien Sunblaze, and Connall Irongrip to determine how they died, then return to Crusader Rhydalla
If indeed these men were murdered, then we must find a way to tie it to the Black Knight before he strikes again. Look closely at what the crystal tells you, <name>, for we must be certain these deaths were not accidental.
Progress
Have you visited the graves of the slain combatants?
Completion
So you say Lorien Sunblaze was done in by poison and Sir Wendell was burnt alive? Dreadful ways to die, both of them. Only Connall was killed by cold steel, and from your description, it was a coward's strike, not honorable combat that laid him in his grave.
All three sparred with and were scheduled to fight the Black Knight. This cannot be a coincidence. Now we must find a way to prove it was the Black Knight's work.
Notes
Due east of the tournament grounds is a decently large graveyard. Use the [Seer's Crystal] on each of the three graves.