Your Clan is matched into Wars, against other Clans based on your Clan’s Trophy count. In other words, all the Clans in a War will have roughly the same amount of Clan Trophies when the War begins.
Clan War or Training & Battle Days
In Clan Wars, you will be primarily matched with players that have a similar Trophy count to you, no matter the league their Clan is in.
To keep the time to find a suitable match as low as possible, matchmaking will expand its search criteria if finding a match takes too long.
The matchmaking system will also consider your personal performance in Clan Wars when matching you with other players.
Clan War Colosseum
Similar to Clan War, your opponents are players with similar Trophy counts who are also searching for a match in the Colosseum.