Hiccup ran into him again while trying to escape the Death Song. While Earsplitter was mad at Hiccup about before, he focused more on fighting the Death Song. They managed to escape and Hiccup trained him to help save the others as the Thunderdrum was immune to the Death Song's call.
After breaking the dragons and riders out of the amber cocoons, Hiccup realized the reason why Earsplitter was fighting the Death Song was that it had captured his son. Hiccup and Toothless lured the Death Song into a cave and Earsplitter blasted it shut, after the duo made it out.
Earsplitter happily reunited with his son and Hiccup recommended the two find a new home, though Tuffnut pointed out that the Thunderdrums couldn't hear him.
Earsplitter is a violet colored Thunderdrum, which looks exactly the same as Whirlwing and Boom. In Rise of Berk, his wings and underside have hints of light blue.