Cyanea
Locations: Mount Celestia / Silver Sea; Ysgard; Bytopia; Outlands / Tir fo Thiunn; River Oceanus (Wandering)
Cyanea, also known as the Jellyfish City, resembles nothing so much as, well, a giant jellyfish, several hundred feet in diameter, surrounded by a shoal of dozens of smaller creatures. Beneath a staggeringly huge swimming bell extend eight tentacles, each almost a thousand feet long. Each tentacle has many hydroids on it, each of which is the size of a small building. Cyanea can usually be found drifting in the River Oceanus, but is known to have been found in Mount Celestia’s Silver Sea, the fjords of Ysgard, major lakes in Bytopia and even in the watery realm of Tir fo Thiunn. The sight of the pulsating bell making its way through the waters is said to be one of the most impressive sights in the multiverse.
All sorts of aquatic creatures can be found accompanying the city, and those of good or neutral alignment are gifted with water breathing in its vicinity. Those who already live in the water find that the water acts as either salt or fresh water for them as appropriate. Although air-breathing creatures could live in the city without worries, most find the whole business disturbing enough that the vast majority of occupants are normally found in water. Dolphins, aquatic elves, nereids, mermen, selkies, sirines, balaenae, delphons, noviere eladrin, zoveri and more all live on, in or around the jellyfish city.
Leader of the city is Dharamonkar (planar ancient gold dragon [she/her] / Believers of the Source / LG), who is accompanied by a court of younger gold and bronze dragons. This kind of government would normally be enough to dissuade any attack, but the tentacles also boast stinging cells that act as though they can detect evil, and better believe they’ll attack it. [AD&D 2e: For every round that an evil creature is within 100 feet of the tentacles, it can expect to have 2d6 cells fire at it with a THAC0 of 15 and doing 1d8 damage. The cells act as silver weapons to determine vulnerability. In addition, the cells inject a poison (save vs. paralysis or be incapacitated through writhing in pain for 2d8 turns].
On one occasion in the distant past, an invading force (whose identity is lost to the ages) made it past even these defences, and was only defeated by a force of nymphs who took to battle unclothed, which devastated the opposing army. This event has given rise to several ribald songs about the event that have withstood the test of time. A merman known as Greengills (planar merman bard [he/him] / NG) is currently regarded as singing the best rendition of this story, although he won’t sing it in front of a genteel audience, “for fear of offending their sensibilities”.
Cyanea has many purposes. Dharamonkar uses it to travel the planes testing individuals who may be ready for ascension, but it is also used as a means of transport for those of good alignment, and it is one of the safest locations on the planes to hide or plan. Durable goods are in short supply, but some of the stinging cells can be removed and fitted into special supple oily containers that resemble wineskins, in which they retain their abilities for one to four days. Experiments are underway to place the stinging cells onto giant sea slugs for use as an underwater cavalry, albeit a somewhat slow cavalry. The large number of aquatic inhabitants undergoes a constant turnover, meaning that the city is a place where the chant flows thick and fast. Little is known of the possible truth behind the rumours that the city occasionally docks at the legendary underwater City of Hydras.
Source: Planewalker.com by Torsten Bernhardt. This burg is a homebrew addition to the lore.