Their web interface lets you manage your collection on a computer, as Manabox is currently a mobile only app
It can be a 4-drop or a 5-drop, and it fixes Phyrexian mana by lowering its starting loyaty, which you don't want at the multiplayer table or Commander where a planeswalker can be attacked three times for each turn in a four-player game
Even so, this effect is a very strong game closer, and I would say with the pass of time and new cards being printed it is inevitable that we will get more ways of accelerating/cheating this into play and winning on the spot
If you don't like decks that draw a lot of hate, then I sadly would caution against picking this one up :( The Precon List Before we talk upgrades, let's take a look at the stock list to see what we're working with: Corrupting Influence is focused solely on Poison counters, an archetype with a rather shallow card pool, but still cobbles together enough of them for a focused deck: I count 40 cards that are on-theme, either with toxic (Blightbelly Rat), infect (Blight Mamba), gives poison counters (Vraska's Fall), proliferates (Contagion Clasp), or benefits from poison some way (Geth's Summons)
Commanders like Azami, Hylda, and Sen Triplets offer unique ways to maintain control and advantage in the game
Casting Cost: Card Type: Enchantment Card Text: , Exile a creature card from your graveyard: Create a 1/1 green Saproling creature token