Code Geass: Hangyaku no Lelouch, 91 Days Recommendations
Avilio is very similar to Lelouch, both are very clever manipulative tacticians, both seek for revenge for the death of their loved ones, although the atmosphere of both shows is way different, regarding the main protagonist these anime are kinda similar, if you like Avilio's character then you will totally love Lelouch Vi Britania.
The main character is very similar to Lelouch in the fact he is manipulative, has to go under a fake alias, wants to work out who exactly killed/injured his family, especially his younger sibling, and almost everything he plans goes exactly to plan. Both are geniuses, and the Mafia families are almost as ruthless as the Brittanian royal family. A definite watch.
Although the setting is dissimilar, both anime's storyline resemble identical dark, vengeful story.
If you enjoy one, you will get thrilled other one in a similar way.
Both shows carry out a carefully crafted revenge, with beautiful endings to them.
Both of the MC want to have revenge. Great storyline. Pretty good character development.