Right off the bat there is a secret room on the first door to the left (from Dante’s perspective with his front facing the viewer). After that, continue around the corner where there will be a Blue Orb fragment floating against the wall. When you defeat the Msiras, slash through the boarded entranceway to the docks. There will be 4 ledges on the left which leads to another Blue Orb fragment. Ahead there will be a floating sphere but before you hit it continue to the door at the end of the path. After getting rid of the Agonofinis’ the door at the top of the staircase will lead you to your next Heart: Quick Heart and right above the stand will be a gold orb. Next, head to the other side of the docks where you should see an Orb Dispenser and a garage door that is another Secret Room. Now return to the floating sphere and activate it by slashing it which will cause the gateway to open. For this, either tap the evade button repeatedly as you reach the gateway or alternatively run with you Devil Trigger equipped with Quick Heart.
Jokatgulm uses her 4 tentacles that have quite a long range as well as the ability to spew out poisonous gas and to summon a large protective dome around her. Slash around the base of her tentacles until they disappear. When this happens, her base will momentarily stop producing the poison gas which gives you the opportunity to slash her neck until she summons her dome which will fling you away so be sure to escape in time.
Head to the garage on the right and you’ll receive a shotgun as well as your motorcycle which will end the mission.