Solda is a name of a group of Xel'naga whom reached a third purity,the purity of Matter.
The Solda had incredible abilities thanks to the purity of matter.Their form looks like a terran/protoss/xel'naga hybrid.The purity of matter allows one to mimic,fuse,use and evolve any form of matter it touches.The Solda actually lived among protoss and terrans.They ascend any purity to Xel'naga in a condition of unmasking them.
Technology
The solda's technology is far different than other xel'naga weapons or inventions.Here are list of known weapons and inventions made and used:
Alberus spycle
Alberus spycle is a spear/sickle weapon that is made of pure light and every 30 seconds it will unleash a laser shockwave if used.The weapon will shift its size if its owner can't use or hold.
Infinity cube
The infinity cube is a pocket dimension storage device that could contain anything in it.Used to jail rebellious species or fallen xel'naga,Amon was to be held there for 120 000 years.
Elphera
Elphera is an ultimate invention that creates and destroy a planet.The weapon is used for creation or home purposes only.Destruction will be catastrophic if it was used to destroy the koprulu sector.
Homeworld
The solda used planet Zolberaga as their base.they originated from the void but lived and stayed there.they destroyed all traces to their existence and homeworld without destroying their tech and culture.