Chandra, Awakened Inferno Let's be honest here
Beyond that, Energy acceleration is usually good
It can also extend the life of your cards
The only decks that existed for some time were ramp decks featuring Field of the Dead, and 22 Small Probe, Big Problem (Gitaxian Probe) Sometimes, it only takes a small and unlikely spell like Gitaxian Probe to cause some serious damage
Five toughness, immune to sorcery speed things should you like and being black heavily limit what actually deals with him and unlike other medium sized no frills fatties you have to kill him, you can't just stale mate and wait for something else
It doubles any source of damage, not just creature attacks, red sources, or burn spells