Thanos sleeper issues: the overlooked Bronze Age keys

Thanos is a pure Bronze Age creation: his first appearance dates to February 1973 in Iron Man #55, written and pencilled by Jim Starlin with co-script by Mike Friedrich. There are no Silver Age Thanos issues — anyone offering you one is selling a reprint or citing a catalogue error. Starlin's foundational run continued through Captain Marvel #25–33 (1973–1974), Warlock #9–15 (1975–1976), and then the modern saga The Infinity Gauntlet #1–6 (1991). That Bronze Age and early-1990s corpus is what structures the secondary market today.

This guide focuses on the secondary issues with upside: the ones seasoned collectors watch before the general public drives prices up. Every number cited comes from either our eBay estimator (minimum 15 active listings) or a documented public sale record. Issues with insufficient eBay volume are treated qualitatively only.

Thanos key issue dashboard with eBay medians (June 2026)

The table below covers only issues where eBay volume meets the reliability threshold (minimum 15 listings). Issues with insufficient volume are excluded from the median column and analysed qualitatively in the sections below.

*The eBay median for Iron Man #55 (€9) reflects a blend of all grades and all printings — ungraded copies, low-grade copies, reprints. It does not represent the value of high-grade CGC copies, which trade several orders of magnitude above that figure.

Iron Man #55 (1973): the headline key, but the median tells only half the story

This is the foundational issue: Iron Man #55 (February 1973, Jim Starlin and Mike Friedrich) simultaneously introduces Thanos, Drax the Destroyer, Mentor, Kronos, and the Blood Brothers. Our estimator returns a median of €9 across 73 listings — but that figure is deeply misleading taken at face value. It reflects the mass of ungraded and low-grade copies that dominate the market. A CGC 9.8 copy sold for $13,025 at ComicLink in 2013, making it one of the most valuable Bronze Age keys in the Marvel universe. The gap between the blended eBay median and what high-grade copies command is one of the widest of any Bronze Age book — anyone collecting this issue needs to understand that distinction from the first purchase.

Captain Marvel #28 (1973): the Bronze Age sleeper

Published in September 1973, Captain Marvel #28 is widely regarded by experienced collectors as the most undervalued Thanos key from the Bronze Age era. It is the first issue to feature Thanos across a full cover and as the central subject of the story — Jim Starlin handles both plot and pencils, with Mike Friedrich co-scripting. The story sees Thanos defeat Drax and seize the Cosmic Cube while the Avengers (Captain America, Iron Man, Scarlet Witch, Vision, Black Panther) join the battle. Our valuation tool does not cover the Captain Marvel (1968) series: no reliable eBay median is available. On the open market, this issue remains substantially less visible than Iron Man #55 despite equivalent narrative importance — which is precisely its appeal for sleeper hunters.

Silver Surfer #44 (1990): the Infinity Gauntlet's true first appearance

This is the modern sleeper most discussed in specialist forums. Silver Surfer #44 (December 1990, Jim Starlin on script, Ron Lim on art) is the first appearance of the Infinity Gauntlet in comics: Thanos has assembled all the Infinity Gems on the gauntlet and demonstrates its power to the Silver Surfer. The limited series The Infinity Gauntlet #1–6 (Starlin/George Pérez/Ron Lim) did not arrive until seven months later, in July 1991. Our estimator returns only 12 listings for this issue — below the 15-listing threshold, so no median is cited. The key status is recognised, but liquidity remains thin: buyers and sellers should expect a narrower market than the headline Thanos keys.

Thanos #13 (2018): the modern key to watch

In a completely different register, Thanos #13 (January 2018, Donny Cates on script, Geoff Shaw on art) is the first appearance of the Cosmic Ghost Rider — Frank Castle (the Punisher), who became a Spirit of Vengeance and then Thanos's herald in a post-apocalyptic future. Cates's "Thanos Wins" arc is one of the most acclaimed runs of the 2010s in the Marvel cosmic universe. Our tool does not cover the Thanos (2016) series: no eBay median is available. Multiple cover variants exist for this issue — the regular cover edition is the standard reference for the first appearance. The character has since headlined his own series and become a favourite among modern-key collectors.

MCU context: why the market stays active

The massive success of the film adaptations has permanently shaped demand for all Thanos keys. Avengers: Infinity War (2018, Josh Brolin as the Mad Titan) grossed approximately $2.05 billion worldwide; Avengers: Endgame (2019) reached $2.79 billion, making it one of the highest-grossing films in cinema history. That mainstream exposure has anchored collector interest in Bronze Age keys — particularly Iron Man #55 — well beyond the traditional collector base, and continues to draw new buyers to the Thanos corner of the market.