Sven is the gymleader of Shadowcove Town and gives all trainers that defeat him the Moonlight badge.

Sven is completely wearing dark clothes and he even had dark spiky hair. He is specialised in dark type pokemon.

POKEMON HE HAS

Nuzleaf
Caught prior to chapter "Fighting against the darkness!"

Mightyena
Caught prior to chapter "Fighting against the darkness!"

Houndoom
Caught prior to chapter "Fighting against the darkness!"

Murkrow
Caught prior to chapter "Fighting against the darkness!"