set theme: 2005, 2006, vikings

one of the shortest theme ever released by the LEGO company.
the idea of vikings theme is great.
but LEGO decided to ceased production of this theme.
since first release,there were 7 sets ever designed.
the biggest set is 7019 viking fortress against the fafnir dragon. released on 2005.
and the smallest set is 7015 viking warrior challenges the fenris wolf. released on 2005.
other sets released on 2005:
7018 viking ship challenges the midgard serpent
7017 viking catapult vs nidhogg dragon
7016 viking boat vs wyvern dragon
sets released on 2006:
7020 army of vikings with heavy artillery wagon
7021 viking double catapult vs the armoured ofnir dragon