Loki brings the trajectory of Arnaldo Baptista from childhood, passing through the most successful phase as leader of the Mutantes, marriage to singer Rita Lee and then separation. He also goes through the depression that devastated his life after the group ended and that led him to attempt suicide, his solo career, rapprochement with his brother and member of the Mutantes, Sérgio Dias, culminating in the band's return in 2006.
| Actor | Role |
|---|---|
 Arnaldo BaptistaSelf | Self |
 Rita LeeSelf (archive footage) | Self (archive footage) |
 Sérgio DiasSelf | Self |
 Tom ZéSelf | Self |
 LobãoSelf | Self |
| AAluizer MalabSelf | Self |
 Lucinha BarbosaSelf | Self |
| CClarisse LeiteSelf | Self |
| RRaphael VilardiSelf | Self |
| AAntônio PeticovSelf | Self |
 Nelson MottaSelf | Self |
 Dinho LemeSelf | Self |
 Gilberto GilSelf | Self |
 Caetano VelosoSelf (archive footage) | Self (archive footage) |
 Chico BuarqueSelf (archive footage) | Self (archive footage) |
 Tárik de SouzaSelf | Self |
 Roberto MenescalSelf | Self |
 Antonio Carlos da FontouraSelf | Self |
 Rogério DupratSelf (archive footage) | Self (archive footage) |
 LiminhaSelf | Self |
| DDevendra BanhartSelf (archive footage) | Self (archive footage) |
 Martha MellingerSelf | Self |
| KKoko GennariSelf | Self |
| LLuiz Carlos CalancaSelf | Self |
| RRegina MirandaSelf | Self |
| GGregory CheskisSelf | Self |
| JJohn UlhoaSelf | Self |
 Kurt CobainSelf (archive footage) | Self (archive footage) |
| BBill BartellSelf | Self |
 Sean Ono LennonSelf | Self |