Killing the owlbear with the cub will break the oath of ancients

I did not see any comment about what happens if you kill the Oathbreaker Knight when he appears in your camp.
Its not really worth it to be honest - see below if you dont want to kill the knight yourself

***SPOILER ALERT***

Took out the knight as soon as i swapped to oathbreaker at level 3 - Tough fight, but Gale and Lae'zel did work as NPCs
Knight had 192 hp and 2 attacks - pretty tough, but with shadows pocket heals & astarion chucking potions we managed.
Knight failed his save for dreadful aspect - then Lae'zel was able to crit a trip shot with her crossbow - then crit a disarming attack with her great axe - rendering the knight almost useless

After killing him - the party gained 90 xp - and he had a +1 Greatsword & 3 javelins - nothing more, nothing less

I am currently level 4 and about to venture into the underdark - and the only effect killing the knight had on the game is that i can now no longer swap back to oath of the ancients

Might be a silly question: are there ways in game to break your oath but not in an evil way? I play a Drow Paladin (for roleplay sake, not gameplay wise obviously) but want to play heavily on the "evil exterior but actually chaotic good", so yeah, any suggestions?

Allowing the Tiefling Girl (Kanon's sister) to kill the caged goblin Sazza will break the oath of devotion as you are allowing her to kill a defenseless being.

Kill Fezzerk after Wyll interrogates him breaks the oath of devotion?

The "How do I become one" section currently implies that betraying the Tieflings when rescuing Lae'zel only breaks your oath if you're Devotion, but I'm an Ancients and just got Oathbreaker for that.

As a Devotion paladin I tried to rush through to get Oathbreaker as quickly as I could as is stated in the wiki and got nothing. Lied to the tieflings, let the goblin die in camp, attacked the bandits at the ruined temple unprovoked so there no way of knowing yet whether or not they're friendly, attacked the scared boar, and nothing happened. But when I shot a random tiefling with a crossbow the event triggered. Don't know what's not letting the event go through with the supposed options listed here but whatever it is it's pretty annoying.

I just broke my oath of Ancients by freeing Sazza in the Druid Cove.

Want to be an oathbreaker? Just play the game! You'll break your oath accidentally in no time.

By getting a killing blow on a goblin in the Blighted Village, without initiating the fight, but after persuading them to let us through, my oath was broken - but as Oath of the Ancients, not devotion. Seems like this is not fine tuned at all.