Blocked in the room of the Sirena Boss

My character is blocked in the boss room of the Sirena.

The boss is bugged and not appearing and as in a Boss Room my character is not allowed to use a portal.

Could you help me to restore my character or bring it back to home?

At the character selection screen, hold the control key before clicking "Play".

That should give you the option to respawn in your hideout or the nearest town.