|Thalassius was built by the Combine Loyalists and is the home of the Kedge. Beneath the ruins-filled surface is the Coral Keep. Dark, wet and cavernous in nature, this area is also home to numerous other sea-dwelling creatures.
As is the case with the Shissar, the Kedge are quite unwelcoming of visitors. One reason for this is the Combine Loyalists who performed experiments on the Kedge, drawing the ire of the Ocean Lord, Prexus, in the process. One can still see the results of those experiments, as the survivors remain in the deepest part of the keep, lurking in and around the laboratories and chambers in which they were held.