nemesis -- Todd

nemesis
nem·e·sis (nm-ss)

n. pl. nem·e·ses (-sz)

1. A source of harm or ruin: Uncritical trust is my nemesis.

2. Retributive justice in its execution or outcome: To follow the proposed course of action is to invite nemesis.

3. An opponent that cannot be beaten or overcome.

4. One that inflicts retribution or vengeance.

5. Nemesis Greek Mythology The goddess of retributive justice or vengeance.

---

[Greek, retribution, the goddess Nemesis, from nemein, to allot; see nem- in Indo-European roots.]

 

In tennis, some players' nemesis is  on the other side of the net, but Todd's nemesis is his hip.