So the story so far is:

This 25 Y.O. wizard 'RAN', who lives in Castleton, did some big marketing trick, which made him super rich, but town folk got angry with him, so he left.

He gets possessed by an Outer God (the player) and goes unconscious and loses his memory. He is found in this state by some men who work for a secret organisation. This organisation has a scientist by the name of CUEBALL, who theorizes that when someone is possessed by an outer god, they lose their memory, and RAN fulfills this criteria, so CUEBALL asks to keep him as a test subject. Also, he suspects that Outer Gods can time travel.

CUEBALL sets up some other subjects there, and lets RAN get familiar with them. He feeds the other subjects some specific information (MIKE, 21, PLANT13). To test his theory, he wipes RAN's memories, and does the interview before letting him inside the facility, so that he has no way of getting that specific information beforehand, unless the time travel thing is true. This can have two outcomes: 1. He does not know that info => nothing found this time,  2. he knows that info => the theory is true. (And an unexpected outcome, which messes with the experiment completely)

The organisation is trying to find out more about Outer Gods, and eventually to gain control over them/rule over them.

When RAN runs away to go back to his village, he regains control, and gets possessed again upon reaching his village. He is still being chased by the org, and Shades and Sharp get some weapons and Shades buys a cursed ringtone from Adrien. Shades kills Grandma and disguises himself as her. RAN manages to run away again. After that, Shades gets a call from his boss (with the same ringtone maybe).

Ran reaches a cursed forest, which has a lot of monsters and is under the effect of a Decay spell. The Decay spell was put in effect by the ADVERSARY (from the game 'There Is Something Here') to destroy everything in the world. This effect is kept under control by a local god. Ran had studied the spell for a long time before the events of the game to let himself create shortcuts and run away quickly whenever needed, and left notes in the forest. This time, under the possession of the outer god, he rediscovers his own notes, since his own memories are wiped when possessed.

Shades and Sharp follow him there and Shades gets known as 'the KNIGHT' (since he is armed with a powerful sword, which can kill those monsters). Ran again escapes from the forest. Then someone (presumably Ran) gets an invitation from an organisation (presumably the same which is chasing him) for Christmas dinner.

Theories:

• Since RAN's grandma is not a normal human/wizard, so must be RAN. Which means he must be some cosmic being, making him a special host for the Outer Gods to try to possess.
• The organisation might know Universal Thief, and might be the same one who made him do everything in the The Deepest Heist
• The monsters in the cursed forest may be the same as the ones we see in parts 1 and 2, which represent the number of restarts.
• The mosters might be appearing due to the Outer Gods' intervention in this world, or, they might be the reason they are intervening, and our final goal may be to finally solve whatever problem is at the root of this, to stop these monsters from destroying everything.
• The cursed ringtone might be what gave Shades and his blade the power to kill the monsters.