At the heart of Richter's The Light in the Forest is the theme of duality, the pairing of unlike traits within the same character. One of the best examples of this theme is Del Hardy. Having grown up in the American colonial period and lived for some time with native Americans, Del is skilled at two languages and two lifestyles. His ease with True Son derives from his being able to think like a Lenni Lenape and to value the Indian concept of adoption. After a long journey into native territory, however, Del is pleased to return to the lifestyle he prefers. He suffers immediate disappointment in having to remain at the Butler household to protect both True Son and the Butlers from misunderstandings, arguments, and potential violence.
A more complex example of duality is the unusual pairing of minister with militia colonel in Parson Elder/Colonel Elder, leader of the fierce Peshtanks. The two sides of this man provoke True Son, whom Elder tries to ease back into white customs. As a parson, he is sensitive to Myra Butler's distress; he understands the hardships of a mother who must discipline a strong-willed son when she really wants to love and console him. With the optimism of a parish pastor, Elder advises her to allow work and peer friendships to help True Son accept the customs and expectations of white teenagers. However, Elder also speaks as the hard-edged, suspicious frontiersman who is a leader of vigilantes. He justifies the drinking of whiskey and rationalizes the need for killing Indians who supposedly pose a threat to Paxton. The conflicting natures of militiaman and minister seem out of place in one person. Clearly, the settling of hostile territory brings out these extremes in people who choose to live on civilization's edge.
The most complex duality in the book is found in True Son. Richter goes to great lengths to depict the boy in a happy mood while hunting, fishing, and camping with Half Arrow and jubilant at the welcome his Lenni Lenape family offers him when he returns to them. However, Richter knows that, historically, such happy endings were unlikely in a land experiencing such desperate racial turmoil.
When True Son and his family recognize dissent among Thitpan's party, they realize that the boy is about to be tested once more. Not only is True Son formally achieving the status of warrior, but he also volunteers for a situation that calls for playacting. By posing as a white boy in danger, he must fool other whites into steering their boat close enough to shore for Thitpan's party to ambush. True Son succeeds at the ruse until he sees a child standing in the boat, and thinks of the unidentified white boy — who is as innocent of racism as Gordie, True Son's white brother — as a hapless, helpless victim. Like the child whom Thitpan's party earlier murdered and scalped, this small white boy does not deserve tribal vengeance for the death of Little Crane. True Son has internalized Cuyloga's instruction not to make war on children. In fact, in his refusal to make war on children, he is really following what he believes is his core Indian belief, and he pays the price for refusing to go along with the attack that could also cost a child his life.
Although he thinks of Gordie, is True Son, the reader must wonder, subconsciously remembering the trauma of his own abduction? At four years old, he probably did miss his white parents at first, and he was undoubtedly frightened initially at being plucked from his home and his play. The child on the boat may possibly have been taken prisoner and adopted as True Son was. True Son, unbeknownst to his conscious mind, may be preventing another child from going through his own scenario.
The shift in duality from Indian to white breaks the tie of adopted son to father. No longer Lenni Lenape, the boy must make his peace with the white world and return to Paxton or else live on the edge between two cultures. Ironically, as his Indian tribe is deciding True Son's fate, "never had he felt more Indian than at this moment."