the notion that the infected townies can also infect is incredibly broken
but
have you ever heard of a cultist? essentially hes a 3p-type role that recruits people into the cult. once he dies, the peoples hes recruited are still a cult.
a more balanced way to theorize what youre thinking might look like this, and im spitballing:
-a game with the cultist is 1 v the rest at the beginning. if town lynches the cultist, the game is over. town wins.
-cultist can recruit once per Night, but has no factional kill. that'd be stupid powerful.
-recruits lose their power. thatd mean there need to be neutralizer roles in the game too, but if recruits kept their power it can easily make the bad guys stupidly overpowered.
-once the cultist dies, no more recruiting.
-if a cult recruit dies, the cultist can still recruit
-town would need to have a killing pr, and would need to be able to have vanilla roles so as to maintain the integrity of cult members that get recruited (its p unfair to have nothing but pr's in a game where cult members dont have powers, and cult members keeping their original powers is incredibly overpowered).
it can work, and personally i think recruit games are dope. but theres a fine line between an interesting way to play out the mechanic and a broken horrible mess