Drop a can into the void and watch what happens
You don't have a can, but if you did and you just so happened to toss it over the edge it would probably just fall out of sight and then get sucked into the vortex. You don't know what actually happens to things that fall into the void but you know that people who get here through astral projection (which is what you are doing now) just wake up.
Combine Gladius and bong to make a BONG GLADIUS.
You cannot modify the Gladius. Its an heirloom. According to the legend it was crafted by a mystic werewolf blacksmith hundreds of years ago. It has been passed down through your people ever since the werewolves migrated from the Antrewoods and established civilization on the surface. It's said to be connected to the souls of it's previous owner. Probably bullstuff but the history is still there and the Werewolf Council would slowly murder you if they found out you modified the sword.
Asend deeper into limbo by sleeping inside your dream.
If its your dream, you should be able to imagine things.
Imagine simple monster and test your fighting skills (aka so we see his attacks and stuff)
That isn't how this place works. It's not the same kind of dream you have when you sleep. You're actually just projecting a copy of yourself into another world constructed of the combined unconsciousnesses of all the people that can enter this world. The only way you can enter this realm is if you're smoking or taking bong hits so you tend to come here a lot. Once the high dies out you "wake up", which means you are forcibly removed from the world. It isn't a fun feeling.
March onward! We have a quest to do.
I think.
Bring up the quest log, surely you are creative enough to have one in your dreams.

Right. Quests... lets see here... Well you have to get into the Vortex Sanctum of the castle so you destroy the vortex. The entry has been locked every time you get here, so you have to find the key. However the key isn't actually a key, it's a person. So you have to find the person-key and open the door into the Vortex Sanctum to destroy the vortex and return the castle's interior to... well, inside the castle. After that you can finally get into the keep. From there... well there is said to be a grand treasure stored there.
You hate this castle. Its been a thorn in your side for too long. But tonight you are going to get that treasure and be done with this horrible place... Now that you think about it, this castle has only been here for a few days. Who could it belong to?
look for anything you can get your furry hands on.

Oh look, a gem. These gems are capable of producing rapid change in the Unconscious Realm. This one is for the Floral Element. Trees and flowers and bushes and what not. There are gems for most elements. Apparently there is a place in this world where you can make these gems using anything you want.