Krallen means "to claw" or "to clutch". It's a strong, visceral verb that paints a much more intense picture than simply "to hold".
In the song, Rammstein uses this word to create a startling and memorable image: "Sie müssen sich an Sterne krallen" (They must claw onto stars). Instead of peaceful celestial beings, this lyric portrays angels desperately clinging to the stars to keep from falling from heaven. This dark and poetic twist is what makes the word so powerful and enticing to learn.
Most people grow up hearing that if you live a good life, you earn a spot in heaven. German industrial metal band Rammstein takes that traditional promise and completely flips it on its head in "Engel" (Angel). The track starts with the standard moral rule: "Wer zu Lebzeit gut auf Erden / wird nach dem Tod ein Engel werden" ("Whoever is good on Earth during their lifetime will become an angel after death"). Sounds peaceful, right? But then the singer looks up and notices something unsettling. Heaven is not a reward here; it is an isolating trap. Up there, these holy beings hide behind the sunlight, cut off from human contact, terrified of plummeting into the void: "Sie müssen sich an Sterne krallen / damit sie nicht vom Himmel fallen" ("They have to cling to stars so they do not fall from the sky").
The song really hits its stride when the perspective shifts straight into the angels' point of view. They only come out after dark ("Erst wenn die Wolken schlafengehn" / "Only when the clouds go to sleep"), shivering with dread and loneliness: "Wir haben Angst und sind allein" ("We are afraid and are alone"). Notice the blunt German idiom "zu Lebzeit" (in life / during one's lifetime) and the old-fashioned directional phrasing "gen Himmel" (towards heaven), which sets up a church-like expectation before tearing it down. It is delightfully bleak, anti-heroic rock: why behave yourself on Earth just to end up terrified and clinging to a distant rock in the dark? The singer makes his choice loud and clear in the famous chorus chant: "Gott weiß ich will kein Engel sein" ("God knows I don't want to be an angel").