Final answer:
Hodr, Balder's brother, was laid on the funeral pyre with Balder because he unintentionally killed Balder under Loki's deceit.
Step-by-step explanation:
In Norse mythology, the figure laid on the funeral pyre with Balder is his brother, Hodr. After Balder's death, Hodr was killed by Vali, Odin's son, born specifically to avenge Balder's death.
This was done because it was Hodr who unintentionally killed Balder, having been tricked by Loki into throwing the fatal mistletoe dart.
Hodr was included in the funeral pyre to symbolize the tragic family consequences of Loki's deceit and the seriousness of Balder's death.
Adding to the fatal destiny, their mother Frith was unable to resurrect Balder from the underworld, making their deaths seem even more tragic and significant within Norse mythology.
Learn more about Balder and Hodr