Generally speaking, though, I don't think that any one is more important than the other two
If you have experience with Kraum and have a rough idea how many cards it draws on average, you'll draw a similar amount with Mangara

Aethersquall Ancient Archipelagore Arixmethes, Slumbering Isle Awoken Horror Biblioplex Kraken Breaching Leviathan Brinelin, the Moon Kraken Charix, the Raging Isle Deep-Sea Kraken Eater of Days Famished Worldsire Glacier Godmaw Grappling Kraken Grozoth Gyruda, Doom of Depths Gyruda, Doom of Depths Hullbreaker Horror Icebreaker Kraken Inkwell Leviathan Isleback Spawn Jokulmorder Kederekt Leviathan Kiora's Dambreaker Kraken Hatchling Kraken of the Straits Krothuss, Lord of the Deep Leviathan Monstrosity of the Lake Nadir Kraken Nemesis of Reason Nimbus Swimmer Pearl Lake Ancient Polar Kraken Reservoir Kraken Rot-Tide Gargantua Scourge of Fleets Segovian Leviathan Shipbreaker Kraken Shoal Kraken Simic Sky Swallower Sin, Spira's Punishment Sin, Unending Cataclysm Sky Swallower Slinn Voda, the Rising Deep Spawning Kraken Starwinder Stormsurge Kraken Stormtide Leviathan Summon: Leviathan The Watcher in the Water Thing from the Deep Tidal Kraken Tolarian Kraken Trench Behemoth Trench Gorger Tromokratis Wrexial, the Risen Deep Xyris, the Writhing Storm

What affects the value of Inkay
UR Ultra Rare Swordsoul of Mo Ye X WATER Level 4 [ WyrmEffect ] ATK 1700 DEF 1800 If this card is Normal or Special Summoned: You can reveal 1 "Swordsoul" card or 1 Wyrm monster in your hand