'The Young and The Restless' Cast Processes Kristoff St. John's Sudden Death: 'He Left an Indelible Mark'

The Young and the Restless cast is paying tribute to co-star Kristoff St. John in the wake of his death.

In the hours following the news that St. John, who played Neil Winters on the CBS soap opera since 1991, had passed away over the weekend at the age of 52, his co-stars flocked to social media to mourn his loss, posting touching tributes to the late actor.

Speaking in a statement to PEOPLE, Eileen Davidson, who portrays Ashley Abbott on The Young and the Restless, wrote that St. John "left an indelible mark" on her.

"An infinite number of hearts are broken because of the passing of Kristoff St. John," Davidson wrote in. "Kristoff was a loving kind generous sweet hilarious gifted human. He left an indelible mark on all who were blessed to know him. I am so grateful to have been able to work with him and laugh with him. My deepest condolences go out to his family and especially his children, who I know he loves so much."

Her words were echoed by a number of other The Young and the Restless stars, who shared their memories of St. John.

"I am still trying to process the news that this dear, dear man is gone. Forgive me if what I say here doesn't come together just right, but I have to say something about [Kristoff]. He deserves as loving a tribute as my early morning sadness can muster," Yvette Nicole Brown wrote in part on Instagram. "#KristoffStJohn was love. Just pure and simple: love. He was the kind of person you meet who you feel like you've known your entire life. He had a gift for making people feel instantly at ease. He could immediately diffuse any nervousness you had."

In a statement released to PEOPLE, St. John's onscreen son, Bryton James, wrote that he was devastated by St. John's loss, stating that the actor was "an unbelievable example of strength."

"There are no words for my devastation," he said. "For the last 15 years, Kristoff St. John has been my other father, my friend and in the beginning, my reason for feeling as though I belonged in the Y&R family. He was an unbelievable example of strength, given what he endured over the course of his life. But most importantly, he taught us all every single day how to choose to have fun with life no matter what. I will miss him forever."

St. John was found unresponsive in his San Fernando Valley home on Sunday. He was pronounced dead by paramedics at the scene. The Los Angeles County Coroner has deferred a cause of death until an "additional investigation" is completed.