<P> In `` Power Outage '' , Cole 's superiors , the demonic Triad , learn that he may have developed genuine romantic feelings for Phoebe ; Cole responds by killing them , forcing him into hiding . Meanwhile , the sisters acquire a target in the red - and - black - skinned demon Belthazor ( Michael Bailey Smith ) . In `` Sleuthing with the Enemy '' , the Charmed Ones discovers Cole and Belthazor are one and the same , but when Cole convinces Phoebe that he , being half human , truly loves her , she fakes his death so that her sisters Piper ( Holly Marie Combs ) and Prue will not hunt for him . </P>
<P> In `` Power Outage '' , Cole 's superiors , the demonic Triad , learn that he may have developed genuine romantic feelings for Phoebe ; Cole responds by killing them , forcing him into hiding . Meanwhile , the sisters acquire a target in the red - and - black - skinned demon Belthazor ( Michael Bailey Smith ) . In `` Sleuthing with the Enemy '' , the Charmed Ones discovers Cole and Belthazor are one and the same , but when Cole convinces Phoebe that he , being half human , truly loves her , she fakes his death so that her sisters Piper ( Holly Marie Combs ) and Prue will not hunt for him . </P>
when do they find out cole is balthazar
when do they find out cole is balthazar
In `` Sleuthing with the Enemy ''
In `` Sleuthing with the Enemy ''