>>47003533it depends
The earliest you can fight him is with a full team of pokemon, at which point not only will 4 of them be shadow pokemon and you have to deal with random shadow rng bullshit but also you won't have a good selection of pokemon/moves to use (especially so if you go straight to him and don't unlock moves for your shadow pokemon first). At the very best you might have faint attack on your Umbreon if it's level 36 but if you take him up first chance then you absolutely will not be that high levelled and all off the readily available shadows are level 30 meaning you're under-levelled in general.
absolute monster of a man