Some comments from Ferdinbeer, the translator from Akame here.
There seem to be a myth going around that Pumpkin can now spew fire. Let me put that to rest once and for all.
1. Chapter 5: Pumpkin description
精神エネルギーを衝撃波として打ち出す銃の帝具 (A firearm teigu that shoots shockwaves using emotional energy as a source). Pumpkin was established to shoot shockwaves, not fire.
2. Chapter 53: Maintenance
セリュー戦後にメンテを重ねて正解だったわ (Good thing I kept up with the maintenance after the battle with Seryu). Merriam Webster Dictionary’s definition #3: “the upkeep of property or equipment.” Maintenance does not allow new abilities. I wish my car maintenance would turn my Toyota Highlander into The Batmobile, but that’s not how maintenance works.
3. Chapter 53: The 火力 line
パンプキンのエネルギーは誰も見たことがない火力へと昇華していた (Pumpkin’s firepower increased to levels no one had ever witnessed before).
First, let’s take 火力which can have two meanings. First definition. 火の燃える勢い。また、燃える火の強さ。(Intensity of a fire. Alternatively, strength of a fire.) Second definition: 銃砲などの火器の威力。(Power of firearms such as guns.) (source: http://dictionary.goo.ne.jp/leaf/jn2/46386/m0u/). Many of you readers thought it’s the first definition. But it’s the second definition. To play devil’s advocate, we can ask the question “but what if Pumpkin didn’t suddenly become a flamethrower, but is now shooting thermal shockwave?” The important nuance to note here is that 火力 specifically has to do with fire. Something has to be burning. For example, 火力発電 (karyoku-hatsuden) is thermal power/steam power generation, but in order to generate steam power, you have to burn coal or some source of fuel. Unlike Rubicante (Bors’ teigu), Pumpkin has no fuel tank to shoot heated attacks. This eliminates the possibility of Pumpkin shooting some sort of a thermal shockwave.
Next, let’s take 昇華 (shouka). The Japanese dictionary definition appropriate for this term is 物事が一段上の状態に高められること。(Source: http://dictionary.goo.ne.jp/leaf/jn2/107572/m0u/ ) which translates to “for something to be raised to a higher state.” That’s where I came to “ …increased to levels…” That to me sounds like Pumpkin was strengthened, not being rebirthed into a fire type and thus suddenly super-effective against ice types.
Also, look at Mine. See how she’s cloaked in whatever Pumpkin is firing? It’s not really a good idea to set yourself on fire, no? Pumpkin’s source of energy is “emotional energy” and that cloak is showing how much emotional energy is being fed to Pumpkin.
Pumpkin received a significant power boost from Mine purposefully invoking danger by charging in by herself and taunting the two strongest characters in the empire, not because it suddenly developed an ability to spew fire.