Fellblade
The Fellblade was the super heavy tank used by the Space Marines during the Great Crusade. The predecessor of the Baneblade, it was one of the largest tanks used during this period.
History
The Fellblade was created during the Great Crusade by the Adeptus Mechanicus for the Space Marine Legions for use during their various crusades. Use of the Fellblade varied between legions, and there was at least one legion, the Raven Guard, who chose not to use the Fellblade at all. After the Horus Heresy, with the majority of traitor legions fleeing into the Eye of Terror, and with the separation of the loyalist legions, those Fellblades that remained were largely abandoned by Space Marine Chapters that no longer had the means to maintain them. Some were given to the Imperial Guard and put into service with early Baneblades.
In the 41st Millenium
Currently, few, if any, Fellblades remain in service with the Space Marines, mostly because they no longer fit the strategy of most chapters, who can no longer rely on the numbers and supplies they had as legions.