Lazarus the Dire Legacy?
There’s a solid chance in my mind Lazarus is leading (secretly or not) the current white mantle. If the remnants of the mantle fled into the Maguuma Jungle, and Lazarus was wounded from the damaged aspect, he would probably try and take refuge with them. From that position he could direct the remnant Mantle, and keep them relevant for over two hundred years. It seems like the bandits have a very large presence in Maguuma, and since they either are or are working with the Mantle, I would guess Lazarus is operating somewhere in that general area (if he didn’t run off into the Mists as soon as the dragons woke up).
If Lazarus is playing a part in the Mantle/bandit situation, I think it’s also possible Lazarus could be in contact with the Inquest and Nightmare Court, seeing as bandits have an alliance with them in the Brisban Wildlands.
As Excelliate said, it’s possible that Lazarus is leading the White Mantle in modern GW2 – we don’t know how long mursaat live, but a lot of the more ancient races live far longer than humans thus far (ogres, dwarves, kodan, and jotun seem to live easily into the triple digits, and forgotten can live into the quadruple digits).
Now take a look at the situation behind the White Mantle:
They’re the leaders of the bandits – though it seems most low level bandits don’t know this. The bandits are united all across Kryta (and in Brisban Wildlands) – those aren’t individual groups! Said bandits are in alliances with centaurs, Inquest, and Nightmare Court. They’re also paid for by the Ministry, and infiltrating the Ministry Guard (two known ministers are working with them: Caudecus and Zamon, the latter gets killed in the personal story). And they have a base in Brisban Wildlands: Fort Vandal, which no one has been able to get near (NPC story wise). Said Fort Vandal seems to be near where the White Mantle fled to in GW1 (northwestern Maguuma Jungle – near the Bloodstone).
So I’m expecting Fort Vandal to become a level 80 dungeon, and I am expecting Caudecus, Lazarus, and Faolain (only living leader of the allies of the bandits) to appear in content that leads west (via the portal in north-central Brisban Wildlands).
Stop treating GW2 as a single story. Each Season and expansion should be their own story.