The music industry veteran, who joined Roc Nation in 2012, helped steer My Chemical Romance's rise to the top and Way reveals she helped him cope at a time in his life when fame and fortune was overwhelming.
"The world is dimmer today, but I will always have your light to get me through," he writes on Instagram.
Grimes also took to social media to rave about her late manager, stating, "I loved you. Boy, did I love you. Life is beautiful, but we are not entitled to it. Cancer has no intention. It's just life and death. So I don't need to cry for you anymore. I think the Gods just wanted you back."
Other tributes have come from former My Chemical Romance guitarist Frank Iero, who called Valencia "one of the kindest most hardworking people," adding she was "the only reason anything got done in the last years" of his band.
"She absolutely kept us sane for way longer than we could have on our own," he adds.
Meanwhile, Way's wife Lindsey has shared she spent quality time with her friend hours before her death.
"I held her hand yesterday and today she's gone," the bassist said. "I was able to tell her how much I loved her, how much better my life was because she was in it. I was fortunate to be able to do that."