This song is about Loki tricking Hodr into killing Baldr.
"Honour your brother's name, unarmed of blind
Let me aid you in your aim, don't stay behind let's
Maim immortality and death to a deity"
This is said by Loki. Hodr was blind, and Loki offered to help him aim a bow at Baldr, which would kill him.
"There's no reason to defend, nothing can harm him
Let's say it's just pretend, extend your arm and
Bend now this fatal bow and with this mistletoe"
Baldr was invincible to everything but mistletoe, so there was no reason for him to defend against any attacks. But Loki knew that he could be killed by mistletoe, so he tricked Baldrs blind brother, Hodr, to shoot a mistletoe arrow at him.
"Grieving, my teeth I grind, I see it now
You mischievous mastermind, for this I vow
You'll pay in a paragon of sorrow, you made my son"
This is said by Odin to Loki. He is upset that Loki made Hodr his "brothers bane" Bane means destruction. So Hodr was his brothers bane.
This song is about Loki tricking Hodr into killing Baldr.
"Honour your brother's name, unarmed of blind Let me aid you in your aim, don't stay behind let's Maim immortality and death to a deity"
This is said by Loki. Hodr was blind, and Loki offered to help him aim a bow at Baldr, which would kill him.
"There's no reason to defend, nothing can harm him Let's say it's just pretend, extend your arm and Bend now this fatal bow and with this mistletoe"
Baldr was invincible to everything but mistletoe, so there was no reason for him to defend against any attacks. But Loki knew that he could be killed by mistletoe, so he tricked Baldrs blind brother, Hodr, to shoot a mistletoe arrow at him.
"Grieving, my teeth I grind, I see it now You mischievous mastermind, for this I vow You'll pay in a paragon of sorrow, you made my son"
This is said by Odin to Loki. He is upset that Loki made Hodr his "brothers bane" Bane means destruction. So Hodr was his brothers bane.