So, I made an alt. I'm not going to make any attempt to hide the fact that it's my alt, so what what are the rules regarding what I can or can't do on my alt? So far, all I've done with it is make this game: https://www.warzone.com/MultiPlayer?GameID=27263536

I would assume that's allowed because I'm on the same team as my alt and I'm making it clear that the other account is my alt. However, what can't I do with it? Am I allowed to play quickmatch on my alt? Am I allowed to invite it to a tournament to be on my team? What's the limit on what I can do with it?

You can't use an alt to your advantage in a game.

This can extend to the ladders, not being allowed to enter an alt in the same ladder at the same time.

I'm not sure if these rules expand to other non-official or official game types (clan wars, etc.) but I assume Fizzer wouldn't have any problem taking draconian overreach if he doesn't like you.

You shall not operate more than one Warzone account that participates in the same game, tournament, ladder, clan war, or in any way gives you an advantage or gives you points or coins.

from https://www.warzone.com/wiki/Rules

You also can't use alts to bypass QM voting limits. This rule is not enforced, as far as I know, but the Santa Claus exception above might apply. For ladders, you also can't have overlapping ladder runs. You have to wait for the games on one account to fully expire before joining the ladder with another. For Clan Wars, you can't have two accounts compete during the same season.

It's acceptable to have multiple accounts on the same team.

Unlike other online Risk-like turn-based strategy games, Warzone is incredibly tolerant of having and using alternate accounts so long as you don't use them to bypass limits or undermine the competitive integrity of the game. Be warned: if you undermine the competitive integrity of the game, you might find yourself one day bearing the horrific torture of running Clan League, so tread lightly!