Proposed Canon
Can enter tunnels, despite being a Heavy Unit.
 First Appearance
 Known Sides
May be related in some fashion to Dwagons (similar appearance, possession of a breath attack).
Alternately, they may be more closely related to Gwiffon in terms of their make-up. Jillian refers to Gwiffons as 'gummy beasts',Erf-b1-p050 and and this does seem to match the appearance of the Sourmanders. Later on, King Slately comments on harvesting Sourmanders LIAB 35 . This may suggest that Sourmanders may serve as a source of food when needed. If both ideas are true it could mean that Gwiffons can also be used as food when resources are low.
The name is a portmanteau of sour and salamander.