[There it was again, that faint echo of something almost nostalgic. The recollection of sharp blue eyes and dark red hair, warping back and forth before the Citadel in streaks of crimson. Stumbling on occasion, but always back up in an instant as though taking his brother's laughter as a challenge.]

[Had Izunia ever thought about those days, after banishing his own brother?]

...

[It wasn't practical to talk like this, with how much taller Ardyn already was. Luscinia's wings fluttered briefly again as Ardyn knelt down next to Yuuri, watching and listening to her in momentary silence.]

If you're ready to leap to blaming yourself, I would have to say that's terribly stupid when you've no recollection of the situation.