The Lads was a nickname for Lord Kermit Tully, his brother Ser Oscar, and Lord Benjicot Blackwood, the young leaders of the riverlands at the end of the Dance of the Dragons. The three youths were supported by Alysanne Blackwood and Lady Sabitha Frey. All were black supporters of Rhaenyra Targaryen's son, the eventual King Aegon III Targaryen.
With the Lads' forces approaching King's Landing and Lord Cregan Stark also marching south on the kingsroad, Lord Corlys Velaryon advised King Aegon II Targaryen to abdicate and join the Night's Watch but was refused. The king was found poisoned later that day, however, and was succeeded by King Aegon III. The lads were welcomed by smallfolk and the gold cloaks when they arrived in the capital, although Mushroom suspects their reception was organized by Lord Larys Strong.
Are you babes in swaddling clothes, to be cozened by flowers and feasts and soft words? Who told you the war was done? The Clubfoot? The Snake? Why, because they wish it done? Because you won your little victory in the mud? Wars end when the defeated bend the knee and not before.—Cregan Stark to the Lads