Kingdom of Connacht
In the rugged northwest of Ireland, we have the Kingdom of Connacht, ruled by the eponymous dynasties of the Connachta. The Connachta consisted of three separate dynasties: the Uí Fiachrach, the Uí Briúin, and the Uí nAilello, each descended from a son of the High King Eochaid Mugmedon (the fourth son, of course, was said to be Niall Noígíallach, ancestor of the Uí Néill). However, at this point in time, the Connachta had yet to spread their grip firmly over the kingdom as they would be found in medieval times; instead, we have a diverse array of other unrelated dynasties ruling various subkingdoms and tribes in Connacht.
In 479, the dominant dynasty of the kingdom is the familiar Uí Fiachrach, the descendants of Fiachrae mac Eochaid. As before, there are two main branches: the Uí Fiachrach Aidhne ruling over the southwest and the Uí Fiachrach Muaidhe in the northwest, as well as the minor kingdom of Tír Amhlaidh and the current royal lineage of Ailill Molt. The Uí Fiachrach remained largely dominant over the kingship until the 8th century, and any of their main branches are in a strong position to contest (or hold) the throne of Connnacht - if not that of Ireland itself.
The Uí Briúin, descendants of Brión mac Eochaid, were a powerful dynasty in the Middle Ages, ruling all of Connacht and extending their conquests into the former territories of Ulaidh and Midhe. However, in 479 they rule little more than their homeland of Maigh Seola, of little political importance since the defeat of Brión at the hands of Fiachrae and his sons. From these humble beginnings, can you replicate the rise of the Uí Briúin, subdue the plain of Mag nAi, conquer the kingdom of Breigne, and ascend to the throne of Connacht - and perhaps become High King as well?
The last of the Connachta is the obscure Uí nAilello, descendants of Ailill mac Eochaid. They fell into obscurity quickly, leaving not even any king names or genealogies, but were probably a dynasty of some importance in northeast Connacht in 479. Can you reverse your destiny and return the forgotten branch of the Connachta back to relevance - and perhaps even triumph over your more powerful cousins?
To the southeast lies the kingdom of the Uí Maine and its various branches, who claimed descent from a prince of the Uí Méith, a dynasty of the Airgíalla. While most of the other kingdoms mentioned here would eventually be eclipsed by the Uí Briúin, the Uí Maine remained strong and largely independent all the way to the English conquest, to the point where the Connachta would later the genealogies to claim the powerful kingdom to be one of their own. There are also two other minor tribes who would become vassals of the Uí Maine: the Soghaine, a distant relative of the Dal nAraidi, and the tribe of the Delbna Nuadat, who claimed to be related to the Dal gCais.
To the north lies the overkingdom of the Luighne Connacht, including the closely related tribe of the Gailenga. These are the same tribes we find fighting off the Ui Neill in their probably original homeland of Brega, though history would be much kinder to the Connacht branches who would remain powerful into the Middle Ages. Just to the south, ruling over the ancient royal seat of Rathcroghan, we have a kingdom of the Ciarraige, a different branch of the tribe of the same name in Munster. The Ciarraige would eventually be defeated by the rising Uí Briúin Ai who would usurp their position on the ancient capital of Connacht and split the kingdom into three. Surely, though, the kings of such an important site deserve a much better fate, and perhaps a provincial crown to go with it...
Finally, spanning the west coast are several minor kingdoms based upon the sea. There is the kingdom of the Uí hMaill, an independent branch of the Uí Briúin; two branches of the Conmaicne, the Conmaicne Mara and Conamaicne Cuile Tolad (a third major branch, the Conmaicne Maigh Rein, would be founded in the territories of Briefne in the early 6th century), relatives of the Ciarraige and Corcu Mruadh; and another branch of the Delbhna, the Delbna Tir Dha Locha. These sea-kings of Connacht never amounted to much, most of them coming under the rule of the Ui Briuin Seola in the 8th century or so - perhaps you can change that.
Release is planned for tonight, possibly tomorrow morning depending.