A UK-BASED start-up headed by Irish entrepreneur Dylan Collins has raised $2.1 million in a seed investment round.

Fight My Monster is an online trading card game aimed at boys aged between seven and 12. The game, which was created by engineer and entrepreneur Dominic Williams, has already notched up more than one million players in Britain and North America. Players can trade virtual cards or battle against monster opponents.

The latest funding round was led by Greycroft Partners, which counts Klout among its investments. Other investors include eVenture Capital Partners, which has backed Groupon and Sonos, and well-known angel investors Jeff Lapin, Jarl Mohn and Josh Resnick, among others.

The latest fundraising will be used to grow the team behind Fight My Monster.

“It got to this point on a tiny amount of money,” said Mr Collins, the executive chairman, adding that it usually takes a significant investment to get as much traction as Fight My Monster has achieved in a competitive games market. “It’s been growing almost entirely virally in the schoolyard. It was nearly running away from where the team was.”

The company plans to add more developers. The technology platform is built on Cassandra, which is an open-source architecture used by companies such as Twitter and Netflix, and is scalable.

“We have incredibly ambitious plans for Fight My Monster,” said Mr Williams, also chief executive.

Mr Collins has already been involved in several successful technology ventures, including founding DemonWare, which was acquired by Activision-Blizzard, and Jolt Online, which he sold to GameStop.