One possible theme could be the danger of advanced technology. Since it's an artilect war novel, it might explore how the development of artificial intellects can lead to a catastrophic war. Another theme could be survival, as in how the characters or different entities try to survive in the midst of this war.
Well, one key point is probably the concept of the 'artilect' which is likely central to the war in the story. Another could be the significance of 'winter' in the title, perhaps it symbolizes a harsh or desolate state of the world during the war. Also, look at the relationships between the characters as they might drive the plot forward in the context of this artilect war.
The theme of despair could also be present. A black winter can represent a time of hopelessness, where the future seems bleak and characters may struggle with finding a reason to keep going. The long, cold nights and unforgiving weather can wear down on their spirits.
Another theme could be the passage of time and how it affects the family. As time goes by, family members grow, change, and their relationships evolve. There might also be a theme of tradition. The Winter family may have certain traditions that they uphold or struggle to uphold in the face of modernity and change.
Survival is likely to be a theme. In a war setting, characters are constantly faced with life - threatening situations and have to find ways to stay alive, both physically and mentally.
One possible theme could be the futility of war. The novel might show through its story how war often leads to destruction and loss without achieving much in the long run.
Power. A war lord is likely to be all about power, whether it's political, military or social power within the context of the story.
One possible theme could be power and corruption. The boy starting the war might initially have good intentions, but as he gains more power in the process of the war, he could be corrupted by it. Another theme could be sacrifice. He may have to sacrifice his own relationships, his normal life, or even his morality to achieve his goals in the war. And of course, there could be a theme of redemption, if he realizes the error of his ways and tries to end the war he started.
How about a story of a lonely old man who finds joy and connection during winter by helping a stray animal survive the cold? It could have themes of kindness and companionship against a wintry backdrop.
One theme could be captivity and freedom. The kidnapped character is obviously in a state of captivity, and the story might be about their journey towards freedom. Another theme could be identity, as the Winter Soldier has a complex identity, and the kidnapped character might have to figure out who he really is. And there could also be a theme of trust, whether the kidnapped character can trust the Winter Soldier or not.
The theme of loneliness could also be present. Winter can be a lonely season, and in the short story, characters might be isolated. The light might be a connection to something or someone, like a distant light from a neighbor's house that makes a lonely character long for company or a sign of hope that they are not completely alone in this cold world.