These are two sword-wielding warriors clad in insect-themed powered armor ✣ and employed by the Corbettite Railway to defend the Wyrm of Limerick train against attackers. It is not entirely clear if they are Corbettite Monks themselves or hired mercenaries in the manner of the Swiss Guard in real-life Europe. It is also unknown if they are actually from the Irish province of Ulster, or if they just continue the Corbettite tendency for Irish-themed names.
In the comic, they are called forth to battle when the Wyrm is attacked by Swartzwalders while en route to Paris. While they take some pretty serious damage, they are able to kill several of the bear-constructs before being defeated (off screen) by Count Wolkerstorfer and his magnetic weapons. Their actions do give the the train's passengers, including Agatha, time to reach the sanctuary cars at the rear of the train, whereupon said cars separate and fly away.
Possibly relevant outside information[]
Probably parody of Ultraman, or the manga series specifically. Cf Nippon 2007 Hugo award forgery ✣ (photo below comic).
The Ulster rugby team are colloquially known as "The Ulster Men".