SssssaSsssssr, also known as Sssssa, Sasr, or simply S is a statue character like IiiiiaIiiiiir, VvvvvaVvvvvvr, NnnnnaNnnnnnr.
However, he is not actually canon and is more of a joke character created by KiIvaKunner. Kiiva has described him as a crybaby and a coward.
The design was originally created to be IiiiiaIiiiiir before Kiiva realized that he already had a canon design. She later drew the design sad and decided to make it a new character, but she regrets this decision.