Loki and Anundr.
Anundr is an enchanted spear, twin to Mjolnir and its equal in power. Bespelled by Frigga, it carries an enchantment that detects the worth of its bearer just as the hammer does, though its standards are a little bit different, to reflect the differences in the brothers. It was meant to be given to Loki when he was sent to take the throne of Jotunheim, but that plan is no longer an option.
Against his wishes, Loki agreed to allow Anundr to test him, fearful the spear would reject him. But Frigga and Thor knew Loki better than he knew himself, and persuaded him to try.
To Loki’s utter shock, Anundr accepted him, testifying for all the Realms to see that his heart was changed, that he was changed, and for the better.