Mysterious chronicle (part 21)

Mysterious chronicle (part 21) is a book found only in Daemonheim. It may appear in front of the dungeon-ending ladder after killing the boss monster.

Written in the year 1890 of the Fourth Age. One of Bilrach's portals malfunctioned and a race of troublesome creatures came in without him noticing. They refer to themselves as the Gorajo, and they were against him from the start. Their culture despises the reanimation of the dead and the summoning of demons. They are able to keep out of sight from him, so Bilrach fears it may be a long fight.

Something to question is if the Gorajo are in their spirit form, as they are as we see them, or in their normal form. If they are in their spirit form, then how are they brought through without the assistance of someone else summoning them? If they aren't in their spirit form, then when and why did they choose to use that form of doing so in the present time?

Perhaps when Bilrach mentions that they can keep out of sight, he references their abilities of entering his dungeons as a spiritual being.

Transcript
Year 1890 of the 4th Age:

I hazard to call it a disaster, but something grossly unwanted has happened. One of my portals malfunctioned and a race of troublesome creatures crept through without me noticing. They refer to themselves as the gorajo and they maneuvered against me from the very start; their culture despises the reanimation of the dead and the summoning of demons, it seems. The backward fools. While my powers are great, they have a habit of keeping out of sight, so I fear this will be a long fight.

Zamorak guide me!