
1-Todoroki siblings from My Hero academy:
The story must be famous but I'll still explain so... Their father the Hero endeavor was obsessed with making a successor who surpasses the number one hero all might.
That's why he married an ice user which is the opposite of his fire quirk, and  his first son "Touya" though has strong fire he had a body that can't endure his own fire, and then there are "Fuyumi" and "Natsu" who has ice quirks and finally "Shoto" who had the quirk the father wished for, the half ice half fire. So their father neglected them all and abused Shoto under the excuse of training, which led to Shoto drifting away from the others, and *somehow* led to the oldest son who was thought to be dead to become a bloody villain.

2- Nacht and Morgen from Black clover:
They are twins, and the older one Nacht uses shadows magic and has a nasty personality, while the younger twin Morgen uses light magic and is very kind, he also joined the magic knights.

Spoiler: >! Nacht didn't get along with his brother though Morgan dreamed of fighting alongside the other.
Their family conducted a forbidden ritual related to demons, and Nacht who has shadow magic participated even though Morgan tried to stop him, and then the ritual almost wiped out the whole family but Morgan sacrificed himself to save Nacht, and now Nacht is working as a magic knight just like his brother was, and he even started tying his hair back and smiling like him. !<

3- itoshi brothers from blue lock:
I didn't really reach that point in blue lock but I heard vaguely about their backstory.
They were very close brothers and dreamed of becoming world class strikers together but when Itoshi Sae went to spain he got a reality hit and returned depressed and crushed, and from then on his relationship with Rin changed even though Rin was obsessed with following in Sae's footsteps.

There are probably more examples for this trope that one could count...  And I'm pretty sure I'll see Itachi and Sasuke in the comments :3



[heart breaking trope] unfortunate/broken sibling relationships. Especially when one or both still love the other but it's complicated.