Despite having four Champions League medals in his collection, he is hungry for a fifth.
"If you have had the feeling of winning the Champions League, you will want it again and again," said Kroos on Tom Junkersdorf's podcast.
"Sometimes a year or two goes by, which is understandable because others want to win it too, but the feeling doesn't disappear once you have experienced it: you want it again. Despite having four Champions Leagues, I want a fifth."
Real Madrid are a club that demands such desire, which Kroos was aware of from the day he arrived.
"The day of my presentation... There were 30,000 people there, not for a match but to see me kick a ball for a few seconds," said Kroos.
"It was different to anything I had seen or experienced. Here success belongs to yesterday; what matters is the present and winning the next trophy."