Small Things

Wait, what? Is it the quest where we take the rocks so Invincible breaks his legs? I ain't doing that quest.

For those who do not know, this is a reference to one of Arthas's earliest stories.

One day Arthas was procrastinating and had to race to meet someone. He rushed his horse, pushing to to jump over gaps and off the path, any shortcut to get him to his destination faster. Invincible would meet disaster when it landed awkwardly on a jump, and broke its legs. Arthas would have to put his horse down, blaming himself for the accident.

This traumatic experience would influence Arthas to always take the most proactive approach to any situation, obviously to a fault and eventual downfall.

TL;DR: Traumatizing a teenager to turn evil in the future.

During this quest you can also gain access to the old Undercity. Useful on characters that haven't done BFA stuff and are stuck in phasing. I went in to report my quests to Sylvanas.

P.S. Arthas was ridiculous - "Oh, sorry Invincible, I got your legs broken. Bye!" and walks away, while when you target the horse it's still alive...