Hero release timeline

• 
  HiraraAssassin · 🌲 Jungle
  17 June 202698 days after the previous
• 
  MarcelSupport · 🛡️ Roam
  11 March 202683 days after the previous

• 
  SoraFighter, Assassin · 🌲 Jungle
  18 December 202592 days after the previous
• 
  ObsidiaMarksman · 🏹 Gold Lane
  17 September 202591 days after the previous
• 
  ZetianMage · 🔮 Mid Lane
  18 June 202591 days after the previous
• 
  KaleaSupport, Fighter · ⚔️ EXP Lane
  19 March 202588 days after the previous

• 
  LukasFighter · ⚔️ EXP Lane
  21 December 202491 days after the previous
• 
  SuyouAssassin, Fighter · 🌲 Jungle
  21 September 202484 days after the previous
• 
  ZhuxinMage · 🔮 Mid Lane
  29 June 2024105 days after the previous
• 
  ChipSupport, Tank · 🛡️ Roam
  16 March 202480 days after the previous

• 
  CiciFighter · ⚔️ EXP Lane
  27 December 202388 days after the previous
• 
  NolanAssassin · 🌲 Jungle
  30 September 202384 days after the previous
• 
  IxiaMarksman · 🏹 Gold Lane
  8 July 202353 days after the previous
• 
  NovariaMage · 🔮 Mid Lane
  16 May 202391 days after the previous
• 
  ArlottFighter, Assassin · 🌲 Jungle
  14 February 202388 days after the previous

• 
  JoyAssassin · 🌲 Jungle
  18 November 202298 days after the previous
• 
  FredrinnFighter, Tank · 🌲 Jungle
  12 August 202280 days after the previous
• 
  JulianAssassin, Fighter · 🌲 Jungle
  24 May 202263 days after the previous
• 
  XavierMage · 🔮 Mid Lane
  22 March 202228 days after the previous
• 
  MelissaMarksman · 🏹 Gold Lane
  22 February 202235 days after the previous
• 
  YinFighter, Assassin · 🌲 Jungle
  18 January 202225 days after the previous

• 
  EdithTank, Marksman · 🛡️ Roam
  24 December 202129 days after the previous
• 
  ValentinaMage · 🔮 Mid Lane
  25 November 202131 days after the previous
• 
  AamonAssassin · 🌲 Jungle
  25 October 202133 days after the previous
• 
  FlorynSupport · 🛡️ Roam
  22 September 202122 days after the previous
• 
  AulusFighter · ⚔️ EXP Lane
  31 August 202139 days after the previous
• 
  NatanMarksman · 🏹 Gold Lane
  23 July 202173 days after the previous
• 
  PhoveusFighter · ⚔️ EXP Lane
  11 May 202125 days after the previous
• 
  GlooTank · 🛡️ Roam
  16 April 202128 days after the previous
• 
  BeatrixMarksman · 🏹 Gold Lane
  19 March 202135 days after the previous
• 
  YveMage · 🔮 Mid Lane
  12 February 202128 days after the previous
• 
  PaquitoFighter, Assassin · 🌲 Jungle
  15 January 202134 days after the previous

• 
  MathildaSupport, Assassin · 🛡️ Roam
  12 December 202035 days after the previous
• 
  BenedettaAssassin, Fighter · 🌲 Jungle
  7 November 202022 days after the previous
• 
  BrodyMarksman · 🏹 Gold Lane
  16 October 202028 days after the previous
• 
  BaratsTank, Fighter · ⚔️ EXP Lane
  18 September 202043 days after the previous
• 
  KhaleedFighter · ⚔️ EXP Lane
  6 August 202048 days after the previous
• 
  Yu ZhongFighter · ⚔️ EXP Lane
  19 June 202034 days after the previous
• 
  Luo YiMage · 🔮 Mid Lane
  16 May 202025 days after the previous
• 
  Popol and KupaMarksman · 🏹 Gold Lane
  21 April 202032 days after the previous
• 
  AtlasTank · 🛡️ Roam
  20 March 202037 days after the previous
• 
  CecilionMage · 🔮 Mid Lane
  12 February 202026 days after the previous
• 
  CarmillaSupport, Tank · 🛡️ Roam
  17 January 202031 days after the previous

• 
  SilvannaFighter · ⚔️ EXP Lane
  17 December 201921 days after the previous
• 
  WanwanMarksman · 🏹 Gold Lane
  26 November 20192 days after the previous
• 
  LingAssassin · 🌲 Jungle
  24 November 201947 days after the previous
• 
  BaxiaTank · 🛡️ Roam
  8 October 201921 days after the previous
• 
  MashaFighter, Tank · 🌲 Jungle
  17 September 201939 days after the previous
• 
  X.BorgFighter · ⚔️ EXP Lane
  9 August 201917 days after the previous
• 
  LyliaMage · 🔮 Mid Lane
  23 July 201928 days after the previous
• 
  DyrrothFighter · ⚔️ EXP Lane
  25 June 201921 days after the previous
• 
  TerizlaFighter, Tank · ⚔️ EXP Lane
  4 June 201917 days after the previous
• 
  FaramisSupport, Mage · 🛡️ Roam
  18 May 201925 days after the previous
• 
  GrangerMarksman · 🏹 Gold Lane
  23 April 201921 days after the previous
• 
  EsmeraldaTank, Mage · 🛡️ Roam
  2 April 201921 days after the previous
• 
  KhufraTank · 🛡️ Roam
  12 March 201919 days after the previous
• 
  GuinevereFighter · ⚔️ EXP Lane
  21 February 201923 days after the previous
• 
  ValeMage · 🔮 Mid Lane
  29 January 201914 days after the previous
• 
  BadangFighter · ⚔️ EXP Lane
  15 January 201928 days after the previous

• 
  KaditaMage, Assassin · 🌲 Jungle
  18 December 20181 days after the previous
• 
  BelerickTank · 🛡️ Roam
  17 December 201813 days after the previous
• 
  HanzoAssassin · 🌲 Jungle
  4 December 201814 days after the previous
• 
  MinsittharFighter · ⚔️ EXP Lane
  20 November 201814 days after the previous
• 
  HarithMage · 🔮 Mid Lane
  6 November 201814 days after the previous
• 
  KimmyMarksman, Mage · 🏹 Gold Lane
  23 October 201820 days after the previous
• 
  LeomordFighter · ⚔️ EXP Lane
  3 October 201815 days after the previous
• 
  ThamuzFighter · ⚔️ EXP Lane
  18 September 201814 days after the previous
• 
  LunoxMage · 🔮 Mid Lane
  4 September 201828 days after the previous
• 
  ClaudeMarksman · 🏹 Gold Lane
  7 August 201814 days after the previous
• 
  AldousFighter · ⚔️ EXP Lane
  24 July 20186 days after the previous
• 
  SelenaAssassin, Mage · 🌲 Jungle
  18 July 201849 days after the previous
• 
  Chang'eMage · 🔮 Mid Lane
  30 May 201823 days after the previous
• 
  UranusTank · 🛡️ Roam
  7 May 201812 days after the previous
• 
  KajaSupport · 🛡️ Roam
  25 April 20188 days after the previous
• 
  HanabiMarksman · 🏹 Gold Lane
  17 April 201856 days after the previous
• 
  GusionAssassin · 🌲 Jungle
  20 February 201814 days after the previous
• 
  AngelaSupport · 🛡️ Roam
  6 February 201841 days after the previous

• 
  PharsaMage · 🔮 Mid Lane
  27 December 201723 days after the previous
• 
  EstesSupport · 🛡️ Roam
  4 December 20177 days after the previous
• 
  ZhaskMage · 🔮 Mid Lane
  27 November 20173 days after the previous
• 
  HelcurtAssassin · 🌲 Jungle
  24 November 20175 days after the previous
• 
  DiggieSupport · 🛡️ Roam
  19 November 201751 days after the previous
• 
  OdetteMage · 🔮 Mid Lane
  29 September 201745 days after the previous
• 
  IrithelMarksman · 🏹 Gold Lane
  15 August 201711 days after the previous
• 
  HarleyAssassin, Mage · 🔮 Mid Lane
  4 August 201730 days after the previous
• 
  KarrieMarksman · 🏹 Gold Lane
  5 July 201710 days after the previous
• 
  RogerFighter, Marksman · 🏹 Gold Lane
  25 June 201797 days after the previous
• 
  MoskovMarksman · 🏹 Gold Lane
  20 March 20176 days after the previous
• 
  JohnsonTank, Support · 🛡️ Roam
  14 March 2017130 days after the previous

• 
  HayabusaAssassin · 🌲 Jungle
  4 November 20167 days after the previous
• 
  LolitaSupport, Tank · 🛡️ Roam
  28 October 201614 days after the previous
• 
  MinotaurTank, Support · 🛡️ Roam
  14 October 201614 days after the previous
• 
  FannyAssassin · 🌲 Jungle
  30 September 20167 days after the previous
• 
  LaylaMarksman · 🏹 Gold Lane
  23 September 20161 days after the previous
• 
  MiyaMarksman · 🏹 Gold Lane
  22 September 201613 days after the previous
• 
  ZilongFighter, Assassin · 🌲 Jungle
  9 September 2016

The wiki gives these heroes a year or month but no day, so they are not placed on the timeline above.

• 2016Akai, Alice, Alucard, Balmond, Bane, Bruno, Chou, Clint, Eudora, Franco, Freya, Gord, Kagura, Karina, Nana, Natalia, Rafaela, Saber, Sun, Tigreal
• 2017Alpha, Argus, Aurora, Cyclops, Gatotkaca, Grock, Hilda, Hylos, Lancelot, Lapu-Lapu, Ruby, Vexana, Yi Sun-shin
• 2018Jawhead, Lesley, Martis, Valir