Title: Colcu mac Domnaill
Content:  Colcu mac Domnaill (died 580) was a member of the Cenél nEógain branch of the northern Uí Néill. He was the son of Domnall Ilchelgach (died 566) and grandson of Muirchertach mac Muiredaig (died 534) and brother of Eochaid mac Domnaill (died 572), considered high kings of Ireland. He ruled as King of Ailech from 572 to 580. The high kingship of Ireland rotated between the Cenél nEógain and Cenél Conaill branches in the late 6th century. Áed mac Ainmuirech (died 598) of the Cenél Conaill was high king at this time. Colcu appears to have challenged Áed but was defeated and slain at the Battle of Druim Meic Erce (Drumhirk, modern County Tyrone) in 580.
Title: Máel Coluim, Earl of Atholl
Content:  Máel Coluim of Atholl was Mormaer of Atholl between 1153/9 and the 1190s. The Chronicle of Holyrood tells us that in 1186 Máel Coluim had an outlaw called Adam mac Domnaill killed at the altar of a church in Coupar, and burned 58 of his associates inside the church. It is possible that this was a son of Domnall mac Uilleim, who claimed the Scottish throne and was revolting against King William I. Máel Coluim is known to have granted the church of Moulin to the Benedictine monks of Dunfermline Abbey. He married Hextilda, the daughter of Uhtred of Tynedale, an Anglo-Saxon baron. He named his son and successor Henry, perhaps in honour of King Henry II of England. However, Hextilda had been married to Richard Comyn who was still alive well after Henry was born—so it is unlikely she was his mother.
Title: Domnall mac Áeda
Content:  He was a member of the Cenél nEógain branch of the Uí Néill dynasty. His father was Áed Findliath mac Néill, High King of Ireland. Another son of Áed Findliath, and half-brother of Domnall himself, was Niall Glúndub. Domnall and Niall Glúndub shared the kingship of Ailech for several years. In 905, the Annals of Ulster reports that the two had prepared to fight before coming to an understanding. In 908, the men campaigned against in Meath against the rival Clann Cholmáin branch of the Uí Néill.
Title: Meic Uilleim
Content:  In 1186, a certain Adam son of Domnall, "the king's outlaw", was killed by Máel Coluim, Mormaer of Atholl, in the sanctuary of the church at Cupar, and the church burnt with 58 of Adam's associates within. It may be that this Adam mac Domnaill was a son of Domnall mac Uilleim. If this is so, then the presence of his son in Cupar, south of the Mounth, reinforces the conviction that Domnall fought, not for the Mormaerdom of Moray, but for the kingship of Scotland. However, his identification is not certain. One reading would give his name as Áed mac Domnaill, and it may be that he should be counted among the MacHeths, the sons of Áed.
Title: Domnall mac Cellaig
Content:  Domnall mac Cellaig (died 728) was a King of Connacht from the Uí Briúin branch of the Connachta. He was the son ofCellach mac Rogallaig (died 705), a previous king. The sept of Ui Briun he belonged to was the Síl Cellaig of Loch Cime. Domnall has been omitted from the king-lists but his reign is attested in the annals. He succeeded Indrechtach mac Muiredaig Muillethan (died 723) as king and ruled 723–728. His son Flaithrí mac Domnaill (died 779) was also a king of Connacht.
Title: Domnall mac Eimín
Content:  fact, Máel Coluim could well have been wary of the ambitions of the Uí Ímair and Orcadians, and it is possible that he decided to remain a neutral player in their struggle against Brian. The evidence that Máel Coluim's mother was a Leinsterwoman, and that Sigurðr was his son-in-law, suggest that Máel Coluim may have been inclined to side with Sitriuc and Sigurðr against Brian. It may be that Domnall's support of Brian stemmed from these close ties of kinship between Máel Coluim and Sigurðr, and that Domnall's presence at Clontarf was a reaction to the threat of this alliance. The fact that Domnall risked—and lost—his 
Title: Domnall mac Áedo
Content:  Domnall mac Áedo (died 642), also known as Domnall II, was a son of Áed mac Ainmuirech and his consort Land, the daughter of Áed Guaire mac Amalgada of Airgíalla. Domnall was High King of Ireland from 628 until his death. He belonged to the Cenél Conaill kindred of the Northern Uí Néill. The year of Domnall's birth is not known, and even an approximation depends on the date of the convention of Druim Cett, which is debated. Certainly he must have been born around 570 at the earliest, and around 590 at the latest. According to Adomnán's Life of Saint Columba, Domnall mac Áedo met Columba at Druim Cett while still 
Title: Domnall mac Taidc
Content:   Domnall was a son of Tadc, son of Toirdelbach Ua Briain, King of Munster. Domnall was, therefore, a member of the Meic Taidc. According to the twelfth-century Banshenchas, Domnall's father married Mór, daughter of Echmarcach mac Ragnaill, King of Dublin and the Isles. This source specifies that the couple had three sons and a daughter: Amlaíb, Bé Binn, Donnchad, and Domnall himself.
Title: Domnall mac Eimín
Content:  the mother of Sitriuc was also from Leinster, and thus possibly a kinsman of Máel Coluim.  The customary allegiance of the people of Mar is unknown, and it is uncertain whether Domnall's part in the fray is evidence that Brian was aligned with Máel Coluim or Findláech. Whilst it is possible that Domnall was lending assistance to Brian on behalf of Máel Coluim —or that Máel Coluim was at least aware of Domnall's alliance and allowed him to campaign overseas —another possibility is that Domnall's actions were undertaken independently of Máel Coluim, and that Domnall did so in the context of settling a private score with Sigurðr. 
Title: Domnall mac Taidc
Content:  Domnall mac Taidc (died 1115) was the ruler of the Kingdom of the Isles, the Kingdom of Thomond, and perhaps the Kingdom of Dublin as well. His father was Tadc, son of Toirdelbach Ua Briain, King of Munster, which meant that Domnall was a member of the Meic Taidc, a branch of the Uí Briain. Domnall's mother was Mór, daughter of Echmarcach mac Ragnaill, King of Dublin and the Isles, which may have given Domnall a stake to the kingship of the Isles. In 1094, Domnall's uncle, Muirchertach Ua Briain, High King of Ireland, drove Gofraid Crobán, King of Dublin and the Isles from Dublin, and may have replaced him with Domnall himself. Certainly at some point following Gofraid's death 

Question: Who is the father of Colcu mac Domnaill?
Answer: Domnall Ilchelgach.
Domnall mac Muirchertaig.
Domnall mac Maic Ercae.
Domnall 'Ilchegach', High King of Ireland.