とも

とも is a particle that can be used either as a sentence-ending particle, conjunction particle, or adverbial particle. Despite this, the meanings are often interchangeable, and it depends mostly on what type of word they are grouped with as to which type of particle it is. Common interpretations of とも in almost any situation are 'even if (A)', or 'no matter if (A)', and it will basically always simply highlight that 'in spite of (A), still (B)'.
As a conjunction particle, とも will be paired with any words that are followed by the auxiliary verbs う, or よう, or after い-Adjectives in their conjunctive form.

• 親(おや)が何(なん)と言(い)おうとも、私(わたし)は彼(かれ)と結婚(けっこん)するつもりだ。
  No matter what my parents say, I intend on marrying him.
• 魚(さかな)がどんなに暴(あば)れようとも、この糸(いと)は絶対(ぜったい)に切(き)れません。
  No matter how violent the fish thrashes around, this line will never break.
• 人生(じんせい)がいくら辛(つら)くとも、諦(あきら)めてはいけない。
  No matter how hard life is, you must not give up.
• いくら下手(へた)であろうとも、毎日(まいにち)練習(れんしゅう)をしていればそのうち上手(じょうず)になれる。
  No matter how bad you are at it, if you practice every day, you will eventually get good at it.

The adverbial particle usage only appears after い-Adjectives in their conjunctive form, and a select number of adverbs. It is recommended not to use this structure after adverbs unless you have already seen it used this way in native material.