Arven is a reoccuring character in the Path of Legends storyline in Pokémon Scarlet and Violet.
Once done, he challenges you to a battle with his strengthened party in order to finish the storyline. It's required if you wish to reach the end game - so best know what you are up against!
Arven battle strategy in Pokémon Scarlet and Violet
Once you find and defeat all five Titans, Arven will challenge you to a final battle to wrap up the Path of Legends storyline. This is much more challenging than his encounter at the very start of the game - so be sure to come equipped with a strong team!
|Fighting, Grass, Ground, Steel and Water
|Grass / Fire
|Flying, Poison and Rock
|Ground / Grass
|Bug, Fire, Flying and Ice
|Water / Ice
|Electric, Fighting, Grass and Rock
Terra Type: Dark
|Bug, Fairy and Fighting
For defeating Arven, you’ll earn 12,600 prize money.
If you want a stronger counter to Arven's Pokémon, then bringing a Fighting-type for openers Greedent and Garganacl, and closers Cloyster and Mabosstiff, is highly advised.
As for those middle two - Scovillain and Toedscreul - both have a weakness to Flying.
That said, you'll want to a few backups as well in case you are caught by surprise - as such, bringing a Grass type for Garganacl and Cloyster in particular is well worth having on standby.
Finally, know that it's Mabosstiff who will Terastallize into a Dark-type to close the battle. If you have a strong Fairy-type there, that will easily do the trick.
Regardless - you'll want a team levelled in the 60s to ensure Arven is managable, even if you are focusing on weaknesses throughout.
With that done, the Path of Legends story is complete! If you haven't already, you'll be hinted that you need more support in order to progress. If it isn't clear, that means finishing the Victory Road and Starfall Street stories, before you progress to the end game.