Thunder Fortress is the boss of stage 4 in Raiden II.
The Thunder Fortress is a multi-part gunwall on rails. Once approached the first part will start moving back, constantly casting lightning bolts which activate various turrets on the platforms above it. The first part is soon joined by two smaller parts and attaches itself to the central one. Once the three moving parts are destroyed the central part will start moving and cast lightning to activate turrets on the sides while shooting at the player.
|Raiden||Desert Spider - Flying Fox - Phalanx MK-III - Gijido - Land Crown - Guardian - Antonov Ma-27 - Doreineji Core|
|Raiden II/DX||Grand Crawler - Death Walkers - Albatross - Battle Axe - Thunder Fortress - Black Bird - Graphite - Huge Satellite - Mother Haven - Gray Nodule|
|Raiden III||BS-01 - BS-02 - BS-03 - BS-04 - BS-05 - BS-06 - BS-07|
|Raiden IV||Exerey Iss - Ordo, Fulas and Mairazard - Famel Ya - Aguen and Ewat - Da Rutura - Isdogaram - Horda Gardia - Horda Gestorada|
|Raiden V||Platon - Great Horn - Kraken - Spice Birds - Blow of Hornet - Messiah - Angel - Humpty Dumpty - Divine Rampart|
|Raiden Fighters 2|
|Raiden Fighters Jet|
|Viper Phase 1|