 In " <unk> Angel " ( 1993 ) , MacLeod and Tessa search for information about newborn Immortal Alfred Cahill ( Martin <unk> ) . Becoming Immortal has made Cahill insane ; he believes he is an angel sent by God to free the world from sin . Cahill starts with the last prostitute he met , Tessa 's old friend , Elaine Trent ( Sandra Nelson ) . Tessa is angry to learn the fate of her intelligent , beautiful friend , but later realizes that she " [ sounds ] like her judge and jury . " MacLeod believes that the only way to stop Cahill is to behead him , despite Tessa 's opinion that " <unk> societies don 't kill their insane . They treat them . " When Cahill comes to the barge looking for MacLeod and finds Tessa alone , Tessa <unk> him by welcoming Cahill as a messenger of God . Later , she tells MacLeod with disgust , " I had to <unk> inside his head ... I had to think like him ... I had to become like him . " 
