User blog comment:JmLyan/Karon, the Sadistic Beast/@comment-24036535-20140604205040/@comment-24036535-20140605002854

A valid point on Spirit Fire, however, it doesn't last for 30 seconds, it isn't a free push tool, I mostly was concerned as to what synergy with itself it has. Also, Darius has to stack his bleed first, he doesn't get that instantly.

Honestly, when you think about it too, self damage isn't that much, just wait for late game, you do little damage to yourself, and a single HP item will be enough to largely remedy the damage, or a lifesteal item like Hydra.