I need help before session 0

[srkinguim]

Next week on May 4th, I will participate in session 0 for out of the abyss, and my master has released races from the Players Handbook and Volo's Guide (vetoed drow and naturally evil races).
So far so good, but he said that if someone was going to use any of Volo's races, they would need a logical explanation (or reason) for that being, that race, to be in the Forgoten Realms.
the races are: aasimar, firbolg, goliath, kenku, lizardfolk, tabaxi, and triton.
So, if I choose one of these races, how could I fit them in these conditions, it can be a very quick summary to just insert in session 0.
Thanks for the help and happy scrolling everyone.

[solidork]

None of those should need any special justification for appearing in the Forgotten Realms. You might need a reason to show up in a specific region, ex: why your Firbolg isn't in the middle of the woods somewhere.

Check out the Forgotten Realms wiki to find out what their default homelands are and think of a reason why they might have left there to end up where the campaign starts.

[Unoriginal]

Next week on May 4th, I will participate in session 0 for out of the abyss, and my master has released races from the Players Handbook and Volo's Guide (vetoed drow and naturally evil races).
So far so good, but he said that if someone was going to use any of Volo's races, they would need a logical explanation (or reason) for that being, that race, to be in the Forgoten Realms.
the races are: aasimar, firbolg, goliath, kenku, lizardfolk, tabaxi, and triton.
So, if I choose one of these races, how could I fit them in these conditions, it can be a very quick summary to just insert in session 0.
Thanks for the help and happy scrolling everyone.

There is no "naturally evil races" in 5e.

Aasimars, Firbolgs, Goliaths, Kenkus, Lizardfolks, Tabaxi and Tritons are all native inhabitants of Toril, so I don't see what kind of justification your DM wants.

[Mastikator]

Well the aasimar can be anyone who has a celestial parent or ancestor, so the only "logistical" reason is just that: a celestial bumped uglies with a mortal and Bob's your uncle.
Goliaths live in mountains AFAIK, and mountains exist in the forgotten realms, so they're you know, an adventurer who ventured fourth, like just pick a mountain.
Lizardfolk are pretty common in forgotten realms, could just be an extra entrepreneurial one.
Tritons live in the oceans, and again, there are oceans in the forgotten realms. Maybe the triton wanted to explore where the land dwellers lived?
Firbolgs mostly live in the feywild but also in the material plane, so like again, a big dude/duddet from the forest that wants to adventure?
I dunno about kenku and tabaxi

[Lunali]

Kenku live in large human cities in the Forgotten Realms, mostly southern Faerun. Your justification is that you decided to be an adventurer.

Tabaxi is the only one that actually might need an explanation as they're from a different continent than the usual. Most tabaxi that crossed the ocean didn't do so by choice, though they may have made their own way since then.

[JellyPooga]

The Sword Coast Adventurer's Guide is actually pretty helpful here. Some of the Background options, alone, can be massive inspiration for some of the more exotic Player Races. Whilst it's other content is unfortunately brief, it does provide a starting point for a broad spectrum of further research, of which there is a trove of lore freely available online, as well as for purchase.