Sage Legacies
Berserker - Sage Ivar Ironside with the title Lionheart.
Assassin - Sage Yuffie Loxley, who bears the title Lufthansa.
Archer - Sage Nira with the title Nightshade.
And lastly, Sage of the arrays - Lin Lehan with the title Sansara Sage.
These four Sages were the grand dukes of Edinburgh. Their names and titles became synonyms with the names of the regions they used to rule which eventually became the four grand duchies of the kingdom.
In Eren's past timeline, the students of LA were allowed to compete in an event in which they could claim the berserker Sage Ivar Ironside's legacy for themselves. This was an event meant only for LA's top-tier students. So of course, he wasn't allowed to see it unfold from the audience zone much less attend it as a participant.
Eren wasn't sure if other academies in the kingdom had similar events on their academy grounds or not. Because the five academies had never come together like this to conduct a joint event.