You are going to get a lot of quests in Mount and Blade 2 and one of these quests include the Rival Gang quest. Here we have prepared a Mount and Blade 2: Bannerlord Rival Gangs quest walkthrough to help you out with this mission.
Mount and Blade 2: Bannerlord Rival Gangs Quest
You are going to be interacting with Snake-eyes Euchor who will tell you about Pacarios Sourwine and his people troubling him. He wants to teach them a lesson and asks for your help. He asks you to meet him in Onira after 3 days.
Once you agree to fight beside him, you activate the quest. Now you should go around in various towns in order to collect some equipment for the attack.
Wear the civilian leather gear and get back to Onira. You have to wait for three in-game days before the quest update pops up and the top of your screen and you will see a red pointer on the quest tab which is at the bottom left of your screen.
Save the game just in case you do not want to start all over again if you lose the fight. You will receive a message from Snake-eyes Euchor who will tell you about the rival gang moving to Onira. You and the gang start to make their way towards the Rival Gang.
Pacarios Sworwine is going to try to buy you out. It’s your choice now, you can either take 3130 denars from him or refuse him and be prepared to fight.
Once you and your gang defeat the Rival Gang, you have completed the quest and you are going to get renown, influence and morale.
Beware as there is a bug going around in the game which causes the Rival Gang to spawn on the rooftops or behind the gate. You have to be quick about it and either make them fall from the rooftop or check that if the leader is near the gate, can you interact with him.