how to beat a seek with sin:
so when the seek is using strength genie just try to stun lock and silence lock and be very precise in timing and u can kill him instantly if u use ur genie skills like relentless courage with ct and some wood or fire pills,doesn't even matter if the seek has campy gear if u have some crit (or maybe even that not needed) lvl r8 gear and GoF daggers.
when using dex genie just wait till seek uses badge of courage and stunlock kill him right after, pretty easy.
if the seek uses earthquake to disrupt ur stun skills then repeat or/and force stealth or expel.
till the seek becomes weak and you can kill him like a mc'nugget