External law fragments affect the consciousness and also limit the amount of stats that transcendents can transform with Origin energy. They also slow down their healing so it is unlikely for an Origin weapon to be easily assimilated. But if it works, then he would gain the powerful body of law of titans of law.
This kind of body of law is not like the weak one gained through bloodlines. Bloodlines grant less than 1% law fragments in the body whereas a true titan of law that broke through from a long of law and whose existence experienced the baptism of the loss of essence from their Origin has a body of law that ranges from 20% to 80%.
That means they will be able to resist up to 20% to 80% of damage from attacks and also gain the amplification of world power by 20% to 80%. A body of law is the next stage of evolution on the path of perfection and it is something to look forward to. Especially since he would be getting it earlier with a soul body.