Hm... Technically speaking... The Kamidogu protected Onaga from 4.57470315962 Kilotons blast (according to this
calc), meaning, a single Kamidogu is capable of protecting Onaga from an attack worth 653.529022 tons of tnt and thus Shujinko is able to shatter objects that is capable of withstanding 653.529022 tons of tnt - but since this is only an "amp" bought by the combined power of the (at least) twenty-six fighters in MK: D, everybody's power is only worth about 25.1357316 Tons normally.
From my own observation of MK: D's intro and playing the arcade mode, the Kamidogu only provide Onaga with immense durability than anything considering the fact that Shang Tsung and Quan Chi's combined attacks can push Onaga back and make him groan in pain and with Raiden's help this effect happened again but to a higher degree and Onaga was even struggling at points to fight against the attack... oh, and of course, characters can "harm" Onaga in Arcade mode but do extremely "little" damage and it is basically a massive help to break all of the Kamidogus if you don't want to cheese Onaga.