As a child, Bécc grew up at a port, near the Doon Fort, where he was taught that nature's waters and winds were spirits and that sacrifices were needed to appease them. Bécc traveled the dangerous waters and soon became experienced at going long distances at sea. Upon accepting the Children of Danu's invitation, Bécc became both a obtainer of foreign weapons for the cult and a strict, firm advisor. As he rose the ranks, Bécc was seen as both a fearful and glorious leader of the cult.
The Viking jarlskona Eivor Varinsdottir of the Raven Clan came across the cryptonym of "The Seed", when she killed The Deer and recovered a clue from The Deer's personal effects. After recovering The Deer's amber shard, Eivor looked over the clue, which was a note to The Deer from The Seed, detailing The Seed's need of more men to train for their cult at Dunseverick fortress. After Bárid mac Ímair's death in a surprise attack by Abbot Eogan mac Cartaigh's army, Eivor traveled back to Dublin to advise the new King of Dublin, Sichfrith. Within the meeting, Eivor calmed down Sichfrith from making any rash choices as Azar walked in to divulge news of halted weapons delivery. Azar mentioned to Eivor that the Children of Danu held the weapons and were led by a member called The Seed. After the meeting ended, Eivor obtained a clue from Azar, who stated that more information could be found at Movilla Abbey, in northeastern Ulster.
Eivor traveled to the abbey and found the note on a pew inside. After the last clue, Eivor deduced the name of The Seed, Bécc mac Nath-í, and his location in Dunseverick Fortress, where he was instructing new recruits. The note was also stated to The Deer, as a parent wanted their kids not to go to war against High King Flann Sinna and begged The Deer to help. Arriving at Dunseverick, Eivor explored the area and caught sight of Bécc at the fortress. Eivor became nearer and assassinated Bécc, ending his power and control for the Children of Danu. Among Bécc's personal effects, Eivor found his amber shard and a note from The Oak about his recent attack on Flann and how their goals were coming close. Putting the pieces together, Eivor deduced that Eogan was the Ollamh Druid of the Children of Danu.
- Assassin's Creed: Valhalla – Wrath of the Druids – Target menu: "Bio: Bécc mac Nath-í, The Seed"
- Assassin's Creed: Valhalla – Wrath of the Druids – Children of Danu
- Assassin's Creed: Valhalla – Wrath of the Druids – The Mask of Diplomacy
- Assassin's Creed: Valhalla – Wrath of the Druids – The Wages of War