Gather other allies first.

You decided to gather other allies first, allies you can trust before searching out Rain and Tanya. Better to prepare for the worst before hoping for the best after all. Though that itself was a challenge at the moment. Your immediate Family were either dead or enslaved zombies working for your enemies, and not many among the warring faction don't know you exist, and no doubt will have a hard time trusting the son of Shao Khan, and some of them are smart enough to figure it out without you telling them, So best to avoid any major player from Earthrealm and Outworld. So you have to look for total strangers who aren't as well known or too active in the grand scheme of things, the better to gather your forces while under everyone else's radar.

Thankfully you know just where to start, Asgarrth your adopted father had many connections and records of names of Edenians who were part of the Resistance while Shao Khan was in power which he made you memorize. Searching from memory one name stood out, Ruby a friend of Kitanna, not as close as Jade but a good friend in their youth until the invasion from Outworld she ended up joined the enemy not out of pride and ambition like Rain or Tanya, but out of fear and pragmatism. Still, last you checked she joined the resistance after Shao Khan was slain and Kotal Khan took over, no doubt inspired by the rising movement and opportunity presented at the time. She is perfect, a Veteran fighter with a small following and no love lost with Rain and Tanya, she would choose you in a heartbeat once you prove your worth and integrity.

Still there are other options to consider, just because you can't approach the main Kombatants, doesn't mean their aren't any potential allies lying in wait or hiding within Earthrealm or Outworld, maybe even the other realms. Netherealm may be very risky but the reward may be worth it, from there you can bring back fallen warriors who can be of use to you such as Milleena and Baraka who can reunite the scattered resistance alone among others. On the other hand maybe it would be best to recruit Ruby and whatever forces she has to help you scout for them