This death doesn't last: Esther brings him back a few years later in the body of the witch Vincent. That eventually ends, but when Davina resurrects Kol during an episode that also acts as TVD crossover guest starring Stefan, she unknowingly resurrects Finn as well with the same spell. That resurrection only lasts for a few more episodes before Finn's final death at the hands of Lucien Castle after Elijah, Finn and Matt work together in a failed attempt to stop him from becoming The Beast. Matt and Finn killing Lucien together actually triggers Lucien's transformation into The Beast.
This death doesn't last: Esther brings him back a few years later in the body of the witch Vincent. That eventually ends, but when Davina resurrects Kol during an episode that also acts as TVD crossover guest starring Stefan, she unknowingly resurrects Finn as well with the same spell. That resurrection only lasts for a few more episodes before Finn's final death at the hands of Lucien Castle after Elijah, Finn and Matt work together in a failed attempt to stop him from becoming The Beast. Matt and Finn killing Lucien together actually triggers Lucien's transformation into The Beast.
There's a reason that this episode was called The Murder of One.