Wow you guys are all wannabe heroes and you're all soooo smart...
/s.
- Why didn't he get rid of the other crystal ? Maybe because he fuckin' didn't KNOW they existed. He found the princess doing things with an artefact, so he immediately destroyed it. How the hell was he supposed to know she had a whole stack of those ? He assumed one artefact did the job. Not a truckload of them.
- Yeah. As if he can just assassinate a princess and a king and get away with it so easily. He'll just get mobbed and hanged at the gate the next day. Hell, if he just went along with it, there's a lot of chance his friend guard captain and subordinate would get immediately executed. They already have assassin's on their trail. Not to mention the guard captain could have just handed him over if the MC did take such rash option without consulting him first.
- How powerful is the princess ? And do you really think the king have no bodyguard ? He managed to get away in this chapter because the guard captain and his subordinate prepared so he could escape soon and the princess didn't do anything to him.
- Dude is 15-6 years old. He's japanese in a peace-loving country that didn't have a single external conflict since 1945. You really think he could have killed someone in cold blood just like that ? Really ? Do YOU think you could have, if YOU were an angsty 16 years old in his place ?
Sure, from an omniscient reader his actions seems retarded. But he's a retarded teenager like all retarded teenager are.