"I've known for a long time that Rick wasn't going to last until the end. That was one of the things [creator] Robert [Kirkman] said to me years ago he was planning but I was never 100 percent sure that he was going to do it," Adlard admitted to Express.
"The book thrives off no one is safe, we've always said that to everybody. I've always been a firm believer that this book could easily survive without Rick. The book isn't called Rick, it's not Spider-Man, it's not Superman."
Adlard, who has served as illustrator on the Kirkman-penned book since 2004, has realized most of the book's biggest moments and deaths. When it came to depicting Rick's assassination, "You realize you're drawing a significant moment and this moment should be honored," Adlard said.
"I have to draw it 'better' because it's a significant moment but as soon as you have those thoughts in your head you're automatically not going to. In the end it's just marks on paper."
The artist couldn't say what's next for the book following its latest major turning point, but Kirkman previously hinted the series will now focus on currently MIA villain-turned-anti-hero Negan.
"I think The Walking Dead universe is very strong and it has enough characters within it take up not just his mantle but take up the story and where we've left off after that," Adlard said. "Believe it or not we've got a few surprises up our sleeves yet to raise some more eyebrows in the fandom."
In the "Letter Hacks" column ending issue 192, Kirkman revealed he plotted out Rick's death nearly a decade ago.
"I've said in interviews for many, many years that everyone dies in this story, and that even Rick Grimes won't survive until the end," Kirkman wrote.
"While this was always Rick's story thus far, as written about in the first issue, that doesn't mean he needs to be alive to be a presence in the series. This is the story of a world, not a man... it's the story of a world profoundly affected by that man, as we'll see starting next issue... but it isn't exclusively Rick's story."
The Walking Dead #193 releases July 3.