Let $A$ be a Banach algebra.
Is there an abelian Banach algebra $A$ without identity so that $\Omega (A)=\varnothing$?
Is there a Banach algebra with identity $A$ so that $\Omega (A)=\varnothing$?
I would like to know whether the abelian and identity are necessary to have $\Omega (A)\neq \varnothing $, where
$$\Omega(A) = \{ \varphi \colon A \longrightarrow \mathbb{C}: \varphi \text{ is a non-zero homomorphism}\}$$
As for your first question, yes, there are such algebras. Please see here.
In the non-abelian case characters are somehow rare. For example, for every Banach space $X$ isomorphic to $X\oplus X$, the unital Banach algebra $B(X)$ comprising all bounded linear operators on $X$ does not have any characters because $B(X)$ is Banach-algebra isomorphic to every matrix algebra $M_n(B(X))$ over itself.