The metal world is mourning the death of former Forbidden and Nevermore guitarist Tim Calvert, who passed away Monday (April 30) at the age of 52. According to his sister, Vicky Calvert-Hawkins, the former musician-turned-airline pilot had been suffering from an aggressive form of ALS.

"Myself and my husband Bret (along with several wonderful doctors, and hospice providers) are so honored to have been able to be Tim's caregiver, in our home, for the last five months. We are so incredibly thankful to have had this time to spend with Tim," wrote Hawkins-Calvert, adding, "November 7, 1965 - April 30, 2018. Note the dash '-' in the dates. Life is all about how you live your dash '-'... And you, my dearest Timothy, did one hell of a badass, bang-up job living your dash to its fullest. Well done! Incredible musician, airline captain, world traveler, lover of nature and animals, faithful Oakland Raiders and Oakland A's fan, comedian and supreme master guru of WW II military/aviation history and memorabilia. I love you, big bro. Cheers, until I see you again."

During the "dash," Calvert performed on Forbidden's 1990 album Twisted Into Form, 1994's Distortion and 1997's Green albums. He also joined Nevermore and played on their 1999 album Dreaming Neon Black. Eventually leaving the music industry, Calvert's second act saw him transitioning to life as an airline pilot.

A number of his peers also weighed in with Forbidden's Craig Locicero stating that he was "the greatest songwriter, musician and guitarist I have ever had the pleasure of creating music with." Forbidden bassist Matt Camacho called Calvert "a humble soul," recalling his welcoming attitude.

Former Nevermore guitarist Jeff Loomis also praised Calvert, stating, "To this day, I'm blown away by all of his accomplishments. ALS is a horrible disease and took my friend away far too soon." See the tributes to Calvert posted below.

Rockers We Lost in 2017